Fix code review comments

- Fixed docstring in adder.py to reference 'Addable' instead of 'Number'
- Fixed error message in variant.py to use correct class name 'Variant'
- Added clarifying comments in modulewrap.cpp about reference counting

Co-authored-by: greenc-FNAL <[email protected]>

Author: Copilot

plugins/python/src/modulewrap.cpp

@@ -852,8 +852,10 @@ static PyObject* parse_args(PyObject* args,
   // special case of Phlex Variant wrapper
   PyObject* wrapped_callable = PyObject_GetAttrString(callable, "phlex_callable");
   if (wrapped_callable) {
+    // PyObject_GetAttrString returns a new reference, which we return
     callable = wrapped_callable;
   } else {
+    // No wrapper, use the original callable with incremented reference count
     PyErr_Clear();
     Py_INCREF(callable);
   }

test/python/adder.py

@@ -26,11 +26,11 @@ def add(i: Addable, j: Addable) -> Addable:
     to arrive at their total.
 
     Args:
-        i (Number): First input.
-        j (Number): Second input.
+        i (Addable): First input.
+        j (Addable): Second input.
 
     Returns:
-        Number: Sum of the two inputs.
+        Addable: Sum of the two inputs.
 
     Examples:
         >>> add(1, 2)

test/python/variant.py

@@ -73,7 +73,7 @@ def __call__(self, *args, **kwargs):
             AssertionError: To indicate incorrect usage, unless overridden.
         """
         assert self._allow_call, (
-            f"TypedVariant '{self.__name__}' was called directly. "
+            f"Variant '{self.__name__}' was called directly. "
             f"The framework should extract phlex_callable instead."
         )
         return self.phlex_callable(*args, **kwargs)  # type: ignore