diff --git a/.pylintrc b/.pylintrc
index 7915322..70735ea 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -34,4 +34,3 @@ disable=fixme,
         too-many-public-methods,
         too-many-statements,
         ungrouped-imports,
-        unidiomatic-typecheck,
diff --git a/src/wuttaweb/forms/base.py b/src/wuttaweb/forms/base.py
index a4a469a..f4dcd9b 100644
--- a/src/wuttaweb/forms/base.py
+++ b/src/wuttaweb/forms/base.py
@@ -330,7 +330,7 @@ class Form:  # pylint: disable=too-many-instance-attributes
         self.model_class = model_class
         self.model_instance = model_instance
         if self.model_instance and not self.model_class:
-            if type(self.model_instance) is not dict:
+            if not isinstance(self.model_instance, dict):
                 self.model_class = type(self.model_instance)
 
         self.set_fields(fields or self.get_fields())