mute isinstance

Author: adamchainz

src/django_mysql/models/functions.py

@@ -466,7 +466,7 @@ def __init__(
             if not hasattr(name, "resolve_expression"):
                 name = Value(name)
 
-            if isinstance(value, dict):
+            if isinstance(value, dict):  # type: ignore [unreachable]
                 raise ValueError("ColumnAdd with nested values is not supported")
             if not hasattr(value, "resolve_expression"):
                 value = Value(value)