Update src/sage/rings/function_field/drinfeld_modules/drinfeld_module.py

Co-authored-by: Antoine Leudière <[email protected]>

Author: xcaruso

src/sage/rings/function_field/drinfeld_modules/drinfeld_module.py

@@ -1775,6 +1775,7 @@ def hom(self, x, codomain=None):
             ValueError: the input does not define an isogeny
 
         """
+        # When `x` is in the function ring (or something that coerces to it):
         if self.function_ring().has_coerce_map_from(x.parent()):
             return self.Hom(self)(x)
         if codomain is None: