add legacy config converter

common/utils.py

@@ -1,6 +1,7 @@
 """Common utility functions"""
 
-from typing import get_args, get_origin
+from types import NoneType
+from typing import Optional, Type, Union, get_args, get_origin
 
 
 def unwrap(wrapped, default=None):
@@ -47,7 +48,7 @@ def flat_map(input_list):
     return [item for sublist in input_list for item in sublist]
 
 
-def is_list_type(type_hint):
+def is_list_type(type_hint) -> bool:
     """Checks if a type contains a list."""
 
     if get_origin(type_hint) is list:
@@ -59,3 +60,16 @@ def is_list_type(type_hint):
         return any(is_list_type(arg) for arg in type_args)
 
     return False
+
+
+def unwrap_optional(type_hint) -> Type:
+    """unwrap Optional[type] annotations"""
+
+    if get_origin(type_hint) is Union:
+        args = get_args(type_hint)
+        if NoneType in args:
+            for arg in args:
+                if arg is not NoneType:
+                    return arg
+
+    return type_hint