diff --git a/src/xopen/__init__.py b/src/xopen/__init__.py
index 88aa828..9014014 100644
--- a/src/xopen/__init__.py
+++ b/src/xopen/__init__.py
@@ -33,7 +33,6 @@
 import subprocess
 import tempfile
 import time
-from abc import ABC, abstractmethod
 from subprocess import Popen, PIPE, DEVNULL
 from typing import (
     Optional,