diff --git a/socials_util/__init__.py b/socials_util/__init__.py
index b067086..243fc42 100644
--- a/socials_util/__init__.py
+++ b/socials_util/__init__.py
@@ -1,15 +1,13 @@
 """Small utility for detecting social websites."""
 
-import datetime
 import re
 import urllib.parse
 from dataclasses import dataclass
-from typing import List, Optional, Set, Union
 
 import aenum
 from enforce_typing import enforce_types
 
-from socials_util._version import __version__
+from socials_util._version import __version__  # noqa: F401
 
 
 class SocialSiteId(aenum.Enum):
@@ -408,7 +406,9 @@ WELL_KNOWN_MASTODON_INSTANCES: frozenset[str] = frozenset(
 def determine_social_from_url_internally(
     url: str,
 ) -> tuple[SocialSiteId | None, str | None]:
-    assert isinstance(url, str)
+    if not isinstance(url, str):
+        msg = f'Url must be {str}'
+        raise TypeError(msg)
 
     # Regexes
     for social_site_url_regex, social_site_id in REGEXES:
diff --git a/test/__init__.py b/test/__init__.py
new file mode 100644
index 0000000..e69de29