diff --git a/sqlmodel/main.py b/sqlmodel/main.py
index 0a7df79..0432bde 100644
--- a/sqlmodel/main.py
+++ b/sqlmodel/main.py
@@ -177,7 +177,7 @@ def Field(
 ) -> Any:
     current_schema_extra = schema_extra or {}
     if default is PydanticUndefined:
-        if type(sa_column) is types.FunctionType: #lambda 
+        if isinstance(sa_column, types.FunctionType): #lambda 
             sa_column_ = sa_column()
         else:
             sa_column_ = sa_column