diff --git a/cf_units/__init__.py b/cf_units/__init__.py
index 33366729..f5c32263 100644
--- a/cf_units/__init__.py
+++ b/cf_units/__init__.py
@@ -568,9 +568,7 @@ def _ud_value_error(ud_err, message):
     if ud_msg:
         message = "{}: {}".format(message, ud_msg)
 
-    message = "[{status}] {message}".format(
-        status=ud_err.status_msg(), message=message
-    )
+    message = "[{status}] {message}".format(status=ud_err.status_msg(), message=message)
 
     return ValueError(message)
 
@@ -613,14 +611,10 @@ def __lt__(self, other):
     # Prevent attribute updates
 
     def __setattr__(self, name, value):
-        raise AttributeError(
-            "Instances of %s are immutable" % type(self).__name__
-        )
+        raise AttributeError("Instances of %s are immutable" % type(self).__name__)
 
     def __delattr__(self, name):
-        raise AttributeError(
-            "Instances of %s are immutable" % type(self).__name__
-        )
+        raise AttributeError("Instances of %s are immutable" % type(self).__name__)
 
     # Declare the attribute names relevant to the ordered and hashable
     #  behaviour.
@@ -753,9 +747,7 @@ def __init__(self, unit, calendar=None):
         )
 
     @classmethod
-    def _new_from_existing_ut(
-        cls, category, ut_unit, calendar=None, origin=None
-    ):
+    def _new_from_existing_ut(cls, category, ut_unit, calendar=None, origin=None):
         # Short-circuit __init__ if we know what we are doing and already
         # have a UT handle.
         unit = cls.__new__(cls)
@@ -903,9 +895,7 @@ def is_long_time_interval(self):
         result = False
         long_time_intervals = ["year", "month"]
         if self.is_time_reference():
-            result = any(
-                interval in self.origin for interval in long_time_intervals
-            )
+            result = any(interval in self.origin for interval in long_time_intervals)
         return result
 
     def title(self, value):
@@ -1113,9 +1103,7 @@ def format(self, option=None):
                     option = [option]
                 for i in option:
                     bitmask |= i
-            encoding = bitmask & (
-                UT_ASCII | UT_ISO_8859_1 | UT_LATIN1 | UT_UTF8
-            )
+            encoding = bitmask & (UT_ASCII | UT_ISO_8859_1 | UT_LATIN1 | UT_UTF8)
             encoding_str = _encoding_lookup[encoding]
             result = _ud.format(self.ut_unit, bitmask)
 
@@ -1221,9 +1209,7 @@ def offset_by_time(self, origin):
         """
 
         if not isinstance(origin, (float, (int,))):
-            raise TypeError(
-                "a numeric type for the origin argument is" " required"
-            )
+            raise TypeError("a numeric type for the origin argument is" " required")
         try:
             ut_unit = _ud.offset_by_time(self.ut_unit, origin)
         except _ud.UdunitsError as exception:
@@ -1304,9 +1290,7 @@ def root(self, root):
                     )
                     raise value_error from None
                 calendar = None
-                result = Unit._new_from_existing_ut(
-                    _CATEGORY_UDUNIT, ut_unit, calendar
-                )
+                result = Unit._new_from_existing_ut(_CATEGORY_UDUNIT, ut_unit, calendar)
         return result
 
     def log(self, base):
@@ -1337,20 +1321,15 @@ def log(self, base):
             try:
                 ut_unit = _ud.log(base, self.ut_unit)
             except TypeError:
-                raise TypeError(
-                    "A numeric type for the base argument is " " required"
-                )
+                raise TypeError("A numeric type for the base argument is " " required")
             except _ud.UdunitsError as exception:
                 value_err = _ud_value_error(
                     exception,
-                    "Failed to calculate logorithmic base "
-                    "of {!r}".format(self),
+                    "Failed to calculate logorithmic base " "of {!r}".format(self),
                 )
                 raise value_err from None
             calendar = None
-            result = Unit._new_from_existing_ut(
-                _CATEGORY_UDUNIT, ut_unit, calendar
-            )
+            result = Unit._new_from_existing_ut(_CATEGORY_UDUNIT, ut_unit, calendar)
         return result
 
     def __str__(self):
@@ -1444,9 +1423,7 @@ def _op_common(self, other, op_func):
                 )
                 raise value_err from None
             calendar = None
-            result = Unit._new_from_existing_ut(
-                _CATEGORY_UDUNIT, ut_unit, calendar
-            )
+            result = Unit._new_from_existing_ut(_CATEGORY_UDUNIT, ut_unit, calendar)
         return result
 
     def __rmul__(self, other):
@@ -1561,9 +1538,7 @@ def __pow__(self, power):
         try:
             power = float(power)
         except ValueError:
-            raise TypeError(
-                "A numeric value is required for the power" " argument."
-            )
+            raise TypeError("A numeric value is required for the power" " argument.")
 
         if self.is_unknown():
             result = self
@@ -1759,16 +1734,14 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                 result = cftime.date2num(
                     result_datetimes, other.cftime_unit, other.calendar
                 )
-                convert_type = isinstance(
-                    value, np.ndarray
-                ) and np.issubsctype(value.dtype, np.floating)
+                convert_type = isinstance(value, np.ndarray) and np.issubsctype(
+                    value.dtype, np.floating
+                )
                 if convert_type:
                     result = result.astype(value.dtype)
             else:
                 try:
-                    ut_converter = _ud.get_converter(
-                        self.ut_unit, other.ut_unit
-                    )
+                    ut_converter = _ud.get_converter(self.ut_unit, other.ut_unit)
                 except _ud.UdunitsError as exception:
                     value_err = _ud_value_error(
                         exception,
@@ -1796,8 +1769,7 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                     # Strict type check of numpy array.
                     if result.dtype.type not in (np.float32, np.float64):
                         raise TypeError(
-                            "Expect a numpy array of '%s' or '%s'"
-                            % np.float32,
+                            "Expect a numpy array of '%s' or '%s'" % np.float32,
                             np.float64,
                         )
                     ctype = result.dtype.type
@@ -1805,15 +1777,11 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                     # _cv_convert_array to convert our array in 1d form
                     result_tmp = result.ravel(order="A")
                     # Do the actual conversion.
-                    _cv_convert_array[ctype](
-                        ut_converter, result_tmp, result_tmp
-                    )
+                    _cv_convert_array[ctype](ut_converter, result_tmp, result_tmp)
                     # If result_tmp was a copy, not a view (i.e. not C
                     # contiguous), copy the data back to the original.
                     if not np.shares_memory(result, result_tmp):
-                        result_tmp = result_tmp.reshape(
-                            result.shape, order="A"
-                        )
+                        result_tmp = result_tmp.reshape(result.shape, order="A")
                         if isinstance(result, np.ma.MaskedArray):
                             result.data[...] = result_tmp
                         else:
@@ -1829,9 +1797,7 @@ def convert(self, value, other, ctype=FLOAT64, inplace=False):
                     result = _cv_convert_scalar[ctype](ut_converter, result)
             return result
         else:
-            raise ValueError(
-                "Unable to convert from '%r' to '%r'." % (self, other)
-            )
+            raise ValueError("Unable to convert from '%r' to '%r'." % (self, other))
 
     @property
     def cftime_unit(self):
diff --git a/cf_units/_udunits2_parser/__init__.py b/cf_units/_udunits2_parser/__init__.py
index 0c7c0111..a669e00e 100644
--- a/cf_units/_udunits2_parser/__init__.py
+++ b/cf_units/_udunits2_parser/__init__.py
@@ -15,8 +15,7 @@
 
 # Dictionary mapping token rule id to token name.
 TOKEN_ID_NAMES = {
-    getattr(udunits2Lexer, rule, None): rule
-    for rule in udunits2Lexer.ruleNames
+    getattr(udunits2Lexer, rule, None): rule for rule in udunits2Lexer.ruleNames
 }
 
 
diff --git a/cf_units/_udunits2_parser/compile.py b/cf_units/_udunits2_parser/compile.py
index b52719c4..24f7c67f 100644
--- a/cf_units/_udunits2_parser/compile.py
+++ b/cf_units/_udunits2_parser/compile.py
@@ -44,9 +44,7 @@ def expand_lexer(source, target):
     with open(source, "r") as fh:
         content = fh.read()
 
-    template = jinja2.Environment(loader=jinja2.BaseLoader).from_string(
-        content
-    )
+    template = jinja2.Environment(loader=jinja2.BaseLoader).from_string(content)
 
     current_mode = "DEFAULT_MODE"
 
diff --git a/cf_units/_udunits2_parser/parser/udunits2Lexer.py b/cf_units/_udunits2_parser/parser/udunits2Lexer.py
index 320d5b63..3d4c33df 100644
--- a/cf_units/_udunits2_parser/parser/udunits2Lexer.py
+++ b/cf_units/_udunits2_parser/parser/udunits2Lexer.py
@@ -1,6 +1,5 @@
 # Generated from /home/ruth/git_stuff/cf-units/cf_units/_udunits2_parser/parser/udunits2Lexer.g4 by ANTLR 4.11.1
 import sys
-from io import StringIO
 
 from antlr4 import *
 
diff --git a/cf_units/_udunits2_parser/parser/udunits2Parser.py b/cf_units/_udunits2_parser/parser/udunits2Parser.py
index ee6d6d1f..30aa96ce 100644
--- a/cf_units/_udunits2_parser/parser/udunits2Parser.py
+++ b/cf_units/_udunits2_parser/parser/udunits2Parser.py
@@ -1,7 +1,6 @@
 # Generated from /home/ruth/git_stuff/cf-units/cf_units/_udunits2_parser/udunits2Parser.g4 by ANTLR 4.11.1
 # encoding: utf-8
 import sys
-from io import StringIO
 
 from antlr4 import *
 
@@ -1384,9 +1383,7 @@ def EOF(self):
             return self.getToken(udunits2Parser.EOF, 0)
 
         def shift_spec(self):
-            return self.getTypedRuleContext(
-                udunits2Parser.Shift_specContext, 0
-            )
+            return self.getTypedRuleContext(udunits2Parser.Shift_specContext, 0)
 
         def getRuleIndex(self):
             return udunits2Parser.RULE_unit_spec
@@ -1460,9 +1457,7 @@ def accept(self, visitor: ParseTreeVisitor):
                 return visitor.visitChildren(self)
 
     def shift_spec(self):
-        localctx = udunits2Parser.Shift_specContext(
-            self, self._ctx, self.state
-        )
+        localctx = udunits2Parser.Shift_specContext(self, self._ctx, self.state)
         self.enterRule(localctx, 2, self.RULE_shift_spec)
         self._la = 0  # Token type
         try:
@@ -1593,9 +1588,7 @@ def product(self, _p: int = 0):
                     _prevctx = localctx
                     self.state = 66
                     self._errHandler.sync(self)
-                    la_ = self._interp.adaptivePredict(
-                        self._input, 7, self._ctx
-                    )
+                    la_ = self._interp.adaptivePredict(self._input, 7, self._ctx)
                     if la_ == 1:
                         localctx = udunits2Parser.ProductContext(
                             self, _parentctx, _parentState
@@ -1717,9 +1710,7 @@ def __init__(
             self.parser = parser
 
         def basic_spec(self):
-            return self.getTypedRuleContext(
-                udunits2Parser.Basic_specContext, 0
-            )
+            return self.getTypedRuleContext(udunits2Parser.Basic_specContext, 0)
 
         def integer(self):
             return self.getTypedRuleContext(udunits2Parser.IntegerContext, 0)
@@ -1805,9 +1796,7 @@ def OPEN_PAREN(self):
             return self.getToken(udunits2Parser.OPEN_PAREN, 0)
 
         def shift_spec(self):
-            return self.getTypedRuleContext(
-                udunits2Parser.Shift_specContext, 0
-            )
+            return self.getTypedRuleContext(udunits2Parser.Shift_specContext, 0)
 
         def CLOSE_PAREN(self):
             return self.getToken(udunits2Parser.CLOSE_PAREN, 0)
@@ -1825,9 +1814,7 @@ def accept(self, visitor: ParseTreeVisitor):
                 return visitor.visitChildren(self)
 
     def basic_spec(self):
-        localctx = udunits2Parser.Basic_specContext(
-            self, self._ctx, self.state
-        )
+        localctx = udunits2Parser.Basic_specContext(self, self._ctx, self.state)
         self.enterRule(localctx, 8, self.RULE_basic_spec)
         try:
             self.state = 90
@@ -1985,9 +1972,7 @@ def INT(self):
             return self.getToken(udunits2Parser.INT, 0)
 
         def signed_clock(self):
-            return self.getTypedRuleContext(
-                udunits2Parser.Signed_clockContext, 0
-            )
+            return self.getTypedRuleContext(udunits2Parser.Signed_clockContext, 0)
 
         def WS(self, i: int = None):
             if i is None:
@@ -1996,9 +1981,7 @@ def WS(self, i: int = None):
                 return self.getToken(udunits2Parser.WS, i)
 
         def timezone_offset(self):
-            return self.getTypedRuleContext(
-                udunits2Parser.Timezone_offsetContext, 0
-            )
+            return self.getTypedRuleContext(udunits2Parser.Timezone_offsetContext, 0)
 
         def DT_T_CLOCK(self):
             return self.getToken(udunits2Parser.DT_T_CLOCK, 0)
@@ -2133,9 +2116,7 @@ def accept(self, visitor: ParseTreeVisitor):
                 return visitor.visitChildren(self)
 
     def signed_clock(self):
-        localctx = udunits2Parser.Signed_clockContext(
-            self, self._ctx, self.state
-        )
+        localctx = udunits2Parser.Signed_clockContext(self, self._ctx, self.state)
         self.enterRule(localctx, 16, self.RULE_signed_clock)
         try:
             self.state = 123
@@ -2195,9 +2176,7 @@ def accept(self, visitor: ParseTreeVisitor):
                 return visitor.visitChildren(self)
 
     def timezone_offset(self):
-        localctx = udunits2Parser.Timezone_offsetContext(
-            self, self._ctx, self.state
-        )
+        localctx = udunits2Parser.Timezone_offsetContext(self, self._ctx, self.state)
         self.enterRule(localctx, 18, self.RULE_timezone_offset)
         try:
             self.state = 127
diff --git a/cf_units/tests/integration/parse/test_parse.py b/cf_units/tests/integration/parse/test_parse.py
index d42b7a36..4bceebde 100644
--- a/cf_units/tests/integration/parse/test_parse.py
+++ b/cf_units/tests/integration/parse/test_parse.py
@@ -167,9 +167,9 @@ def test_invalid_units(_, unit_str):
         cf_valid = False
 
     # Double check that udunits2 can't parse this.
-    assert (
-        cf_valid is False
-    ), "Unit {!r} is unexpectedly valid in UDUNITS2".format(unit_str)
+    assert cf_valid is False, "Unit {!r} is unexpectedly valid in UDUNITS2".format(
+        unit_str
+    )
 
     try:
         normalize(unit_str)
@@ -234,9 +234,7 @@ def test_invalid_in_udunits_but_still_parses(_, unit_str, expected):
 ]
 
 
-@pytest.mark.parametrize(
-    "_, unit_str, expected", multi_enumerate(known_issues)
-)
+@pytest.mark.parametrize("_, unit_str, expected", multi_enumerate(known_issues))
 def test_known_issues(_, unit_str, expected):
     # Unfortunately the grammar is not perfect.
     # These are the cases that don't work yet but which do work with udunits.
diff --git a/cf_units/tests/integration/test__Unit_date2num.py b/cf_units/tests/integration/test__Unit_date2num.py
index 32cbcff8..c724d20e 100644
--- a/cf_units/tests/integration/test__Unit_date2num.py
+++ b/cf_units/tests/integration/test__Unit_date2num.py
@@ -4,7 +4,6 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Test method :meth:`cf_units.Unit.date2num`."""
 
-
 import cftime
 import pytest
 
diff --git a/cf_units/tests/integration/test__Unit_num2date.py b/cf_units/tests/integration/test__Unit_num2date.py
index 11d4c1c3..d39c0ad0 100644
--- a/cf_units/tests/integration/test__Unit_num2date.py
+++ b/cf_units/tests/integration/test__Unit_num2date.py
@@ -249,9 +249,7 @@ def test_fractional_second_360_day(self):
 
     def test_pydatetime_wrong_calendar(self):
         unit = cf_units.Unit("days since 1970-01-01", calendar="360_day")
-        with pytest.raises(
-            ValueError, match="illegal calendar or reference date"
-        ):
+        with pytest.raises(ValueError, match="illegal calendar or reference date"):
             unit.num2date(
                 1,
                 only_use_cftime_datetimes=False,
diff --git a/cf_units/tests/integration/test_num2date.py b/cf_units/tests/integration/test_num2date.py
index 4f067e7b..f831ff29 100644
--- a/cf_units/tests/integration/test_num2date.py
+++ b/cf_units/tests/integration/test_num2date.py
@@ -4,7 +4,6 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Test function :func:`cf_units.num2date`."""
 
-
 import pytest
 
 from cf_units import num2date
@@ -12,9 +11,7 @@
 
 class Test:
     def test_num2date_wrong_calendar(self):
-        with pytest.raises(
-            ValueError, match="illegal calendar or reference date"
-        ):
+        with pytest.raises(ValueError, match="illegal calendar or reference date"):
             num2date(
                 1,
                 "days since 1970-01-01",
diff --git a/cf_units/tests/integration/test_num2pydate.py b/cf_units/tests/integration/test_num2pydate.py
index 7067c4c9..fbc51949 100644
--- a/cf_units/tests/integration/test_num2pydate.py
+++ b/cf_units/tests/integration/test_num2pydate.py
@@ -19,7 +19,5 @@ def test_num2pydate_simple(self):
         assert isinstance(result, datetime.datetime)
 
     def test_num2pydate_wrong_calendar(self):
-        with pytest.raises(
-            ValueError, match="illegal calendar or reference date"
-        ):
+        with pytest.raises(ValueError, match="illegal calendar or reference date"):
             num2pydate(1, "days since 1970-01-01", calendar="360_day")
diff --git a/cf_units/tests/test_coding_standards.py b/cf_units/tests/test_coding_standards.py
index 98cf40e7..08fd3bbe 100644
--- a/cf_units/tests/test_coding_standards.py
+++ b/cf_units/tests/test_coding_standards.py
@@ -28,9 +28,7 @@
 exclusion = ["Makefile", "make.bat", "build"]
 DOCS_DIRS = glob(os.path.join(DOCS_DIR, "*"))
 DOCS_DIRS = [
-    DOC_DIR
-    for DOC_DIR in DOCS_DIRS
-    if os.path.basename(DOC_DIR) not in exclusion
+    DOC_DIR for DOC_DIR in DOCS_DIRS if os.path.basename(DOC_DIR) not in exclusion
 ]
 
 
@@ -104,9 +102,7 @@ def test_license_headers(self):
             last_change_by_fname = self.last_change_by_fname()
         except ValueError:
             # Caught the case where this is not a git repo.
-            return pytest.skip(
-                "cf_units installation did not look like a " "git repo."
-            )
+            return pytest.skip("cf_units installation did not look like a " "git repo.")
 
         failed = False
         for fname, last_change in sorted(last_change_by_fname.items()):
@@ -126,6 +122,4 @@ def test_license_headers(self):
                         failed = True
 
         if failed:
-            raise AssertionError(
-                "There were license header failures. See stdout."
-            )
+            raise AssertionError("There were license header failures. See stdout.")
diff --git a/cf_units/tests/test_unit.py b/cf_units/tests/test_unit.py
index 6bc1ad82..d1e422b8 100644
--- a/cf_units/tests/test_unit.py
+++ b/cf_units/tests/test_unit.py
@@ -164,9 +164,7 @@ def test_format_multiple_options(self):
     def test_format_multiple_options_utf8(self):
         u = Unit("watt")
         assert (
-            u.format(
-                [cf_units.UT_NAMES, cf_units.UT_DEFINITION, cf_units.UT_UTF8]
-            )
+            u.format([cf_units.UT_NAMES, cf_units.UT_DEFINITION, cf_units.UT_UTF8])
             == "meter²·kilogram·second⁻³"
         )
 
@@ -889,9 +887,7 @@ def test_multidim_masked(self):
 
         # Manufacture a Fortran-ordered nd array to be converted.
         orig = (
-            np.ma.masked_array(
-                np.arange(4, dtype=np.float32), mask=[1, 0, 0, 1]
-            )
+            np.ma.masked_array(np.arange(4, dtype=np.float32), mask=[1, 0, 0, 1])
             .reshape([2, 2])
             .T
         )
@@ -971,9 +967,7 @@ def test_num2date_wrong_calendar(self):
             "hours since 2010-11-02 12:00:00",
             calendar=cf_units.CALENDAR_360_DAY,
         )
-        with pytest.raises(
-            ValueError, match="illegal calendar or reference date"
-        ):
+        with pytest.raises(ValueError, match="illegal calendar or reference date"):
             u.num2date(
                 1,
                 only_use_cftime_datetimes=False,
@@ -1003,9 +997,7 @@ def test_num2pydate_wrong_calendar(self):
             "hours since 2010-11-02 12:00:00",
             calendar=cf_units.CALENDAR_360_DAY,
         )
-        with pytest.raises(
-            ValueError, match="illegal calendar or reference date"
-        ):
+        with pytest.raises(ValueError, match="illegal calendar or reference date"):
             u.num2pydate(1)
 
 
diff --git a/cf_units/tests/unit/test__udunits2.py b/cf_units/tests/unit/test__udunits2.py
index 973c8a31..607c60a3 100644
--- a/cf_units/tests/unit/test__udunits2.py
+++ b/cf_units/tests/unit/test__udunits2.py
@@ -67,19 +67,17 @@ def test_parse(self):
         assert unit is not None
 
     def test_parse_latin1(self):
-        angstrom = _ud.parse(self.system, b"\xe5ngstr\xF6m", _ud.UT_LATIN1)
+        angstrom = _ud.parse(self.system, b"\xe5ngstr\xf6m", _ud.UT_LATIN1)
 
         assert angstrom is not None
 
     def test_parse_ISO_8859_1(self):
-        angstrom = _ud.parse(self.system, b"\xe5ngstr\xF6m", _ud.UT_ISO_8859_1)
+        angstrom = _ud.parse(self.system, b"\xe5ngstr\xf6m", _ud.UT_ISO_8859_1)
 
         assert angstrom is not None
 
     def test_parse_UTF8(self):
-        angstrom = _ud.parse(
-            self.system, b"\xc3\xa5ngstr\xc3\xb6m", _ud.UT_UTF8
-        )
+        angstrom = _ud.parse(self.system, b"\xc3\xa5ngstr\xc3\xb6m", _ud.UT_UTF8)
 
         assert angstrom is not None
 
@@ -222,9 +220,7 @@ def test_encode_date(self):
         assert self.date_encoding == res_date_encoding
 
     def test_encode_clock(self):
-        res_clock_encoding = _ud.encode_clock(
-            self.hours, self.minutes, self.seconds
-        )
+        res_clock_encoding = _ud.encode_clock(self.hours, self.minutes, self.seconds)
 
         assert self.clock_encoding == res_clock_encoding
 
@@ -259,9 +255,7 @@ def test_decode_time(self):
             self.minutes,
         )
         assert (
-            res_seconds - res_resolution
-            < self.seconds
-            < res_seconds + res_resolution
+            res_seconds - res_resolution < self.seconds < res_seconds + res_resolution
         )
 
 
diff --git a/cf_units/tests/unit/unit/test_Unit.py b/cf_units/tests/unit/unit/test_Unit.py
index 2293cbae..5d80d75c 100644
--- a/cf_units/tests/unit/unit/test_Unit.py
+++ b/cf_units/tests/unit/unit/test_Unit.py
@@ -4,7 +4,6 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Unit tests for the `cf_units.Unit` class."""
 
-
 import numpy as np
 import pytest
 
@@ -213,9 +212,7 @@ class Test_convert__result_ctype:
 
     def setup_method(self):
         self.initial_dtype = np.float32
-        self.degs_array = np.array(
-            [356.7, 356.8, 356.9], dtype=self.initial_dtype
-        )
+        self.degs_array = np.array([356.7, 356.8, 356.9], dtype=self.initial_dtype)
         self.deg = cf_units.Unit("degrees")
         self.rad = cf_units.Unit("radians")
 
@@ -255,15 +252,11 @@ def setup_method(self):
         )
 
     def test_no_type_conversion(self):
-        result = self.deg.convert(
-            self.degs_array, self.rad, ctype=cf_units.FLOAT32
-        )
+        result = self.deg.convert(self.degs_array, self.rad, ctype=cf_units.FLOAT32)
         np.testing.assert_array_almost_equal(self.rads_array, result)
 
     def test_type_conversion(self):
-        result = self.deg.convert(
-            self.degs_array, self.rad, ctype=cf_units.FLOAT64
-        )
+        result = self.deg.convert(self.degs_array, self.rad, ctype=cf_units.FLOAT64)
         np.testing.assert_array_almost_equal(self.rads_array, result)
 
 
@@ -271,9 +264,7 @@ class Test_is_long_time_interval:
     @staticmethod
     def test_deprecated():
         unit = Unit("seconds since epoch")
-        with pytest.warns(
-            DeprecationWarning, match="This method is no longer needed"
-        ):
+        with pytest.warns(DeprecationWarning, match="This method is no longer needed"):
             _ = unit.is_long_time_interval()
 
     def test_short_time_interval(self):
diff --git a/cf_units/util.py b/cf_units/util.py
index 2f5841bf..dd49af84 100644
--- a/cf_units/util.py
+++ b/cf_units/util.py
@@ -79,9 +79,7 @@ def __new__(cls, name, bases, namespace):
                 )
                 exec(method_source, namespace)
 
-        return super(_MetaOrderedHashable, cls).__new__(
-            cls, name, bases, namespace
-        )
+        return super(_MetaOrderedHashable, cls).__new__(cls, name, bases, namespace)
 
 
 class _OrderedHashable(Hashable, metaclass=_MetaOrderedHashable):
diff --git a/setup.py b/setup.py
index d508892c..f895cc70 100644
--- a/setup.py
+++ b/setup.py
@@ -133,9 +133,7 @@ def _set_builtin(name, value):
     library_dirs=library_dirs,
     libraries=["udunits2"],
     define_macros=DEFINE_MACROS,
-    runtime_library_dirs=(
-        None if sys.platform.startswith("win") else library_dirs
-    ),
+    runtime_library_dirs=(None if sys.platform.startswith("win") else library_dirs),
 )
 
 if cythonize: