diff --git a/src/setuptools_dso/dsocmd.py b/src/setuptools_dso/dsocmd.py
index 70bb7d9..8b5c5c8 100644
--- a/src/setuptools_dso/dsocmd.py
+++ b/src/setuptools_dso/dsocmd.py
@@ -722,7 +722,6 @@ def run_command(self, cmd):
 # if right_before is specified build_dso is injected before that command
 # instead of as first dependency.
 def _needs_builddso(command, right_before=None):
-    assert issubclass(command, Command)
     # copy to avoid changing base class if sub_commands was just inherited
     _ = command.sub_commands[:]
     where = 0