diff --git a/fire/inspectutils.py b/fire/inspectutils.py
index 268150ec..ca35bc12 100644
--- a/fire/inspectutils.py
+++ b/fire/inspectutils.py
@@ -144,7 +144,6 @@ def Py3GetFullArgSpec(fn):
 
   if sig.return_annotation is not sig.empty:
     annotations['return'] = sig.return_annotation
-  
   for param in sig.parameters.values():
     kind = param.kind
     name = param.name
@@ -166,10 +165,13 @@ def Py3GetFullArgSpec(fn):
       varkw = name
     if param.annotation is not param.empty:
       annotations[name] = param.annotation
-      if "Union" in str(annotations[name]):
-        union_type_tuple = get_args(annotations[name])
-        annotations[name] = union_type_tuple[0]
-
+      if "Optional" in str(annotations[name]) or "Union" in str(annotations[name]):
+        tuple_param1 = get_args(annotations[name])[0].__name__
+        tuple_param2 = get_args(annotations[name])[1].__name__
+        if str(tuple_param2) != "NoneType":
+          annotations[name] = tuple_param1 + ", " + tuple_param2
+        else:
+          annotations[name] = tuple_param
     # pylint: enable=protected-access
 
   if not kwdefaults: