Iterable Workaround (#737)

Co-authored-by: Jason Liu <jxnl@users.noreply.github.com>

instructor/dsl/simple_type.py

@@ -31,14 +31,27 @@ def __class_getitem__(cls, response_model: type[BaseModel]) -> type[BaseModel]:
         )
 
 
+def validateIsSubClass(response_model: type):
+    """
+    Temporary guard against issues with generics in Python 3.9
+    """
+    import sys
+
+    if sys.version_info < (3, 10):
+        if len(typing.get_args(response_model)) == 0:
+            return False
+        return issubclass(typing.get_args(response_model)[0], BaseModel)
+    return issubclass(response_model, BaseModel)
+
+
 def is_simple_type(
     response_model: type[BaseModel] | str | int | float | bool | typing.Any,
 ) -> bool:
     # ! we're getting mixes between classes and instances due to how we handle some
     # ! response model types, we should fix this in later PRs
 
     try:
-        if isclass(response_model) and issubclass(response_model, BaseModel):
+        if isclass(response_model) and validateIsSubClass(response_model):
             return False
     except TypeError:
         # ! In versions < 3.11, typing.Iterable is not a class, so we can't use isclass