Only consider arguments when they're handed over

The idea is to keep `undefined` values when users don't explicitly set
`None`. We still want some hackery to hide `start_cursor=None` from
the API thought, because practicality beats purity. :)

notion_client/helpers.py

@@ -3,59 +3,13 @@
 from urllib.parse import urlparse
 from uuid import UUID
 
-NOT_NULLABLE = (
-    "after",
-    "ai_block",
-    "archived",
-    "audio",
-    "bookmark",
-    "breadcrumb",
-    "bulleted_list_item",
-    "callout",
-    "code",
-    "description",
-    "discussion_id",
-    "divider",
-    "embed",
-    "equation",
-    "file",
-    "filter",
-    "heading_1",
-    "heading_2",
-    "heading_3",
-    "image",
-    "is_inline",
-    "link_to_page",
-    "numbered_list_item",
-    "page_size",
-    "pdf",
-    "properties",
-    "query",
-    "quote",
-    "sort",
-    "sorts",
-    "start_cursor",
-    "synced_block",
-    "table",
-    "table_of_contents",
-    "table_row",
-    "template",
-    "title",
-    "to_do",
-    "toggle",
-    "type",
-    "video",
-)
-
 
 def pick(base: Dict[Any, Any], *keys: str) -> Dict[Any, Any]:
     """Return a dict composed of key value pairs for keys passed as args."""
     result = {}
     for key in keys:
-        value = base.get(key)
-        if value is None and key in NOT_NULLABLE:
-            continue
-        result[key] = value
+        if key in base and key != "start_cursor":
+            result[key] = base.get(key)
     return result