code: def is_observing_method(self, prop_name, method):
          
          if (prop_name, method) in self.__PAT_METH_TO_KWARGS:
              return True
          if method in self.__METH_TO_PAT:
              pat = self.__METH_TO_PAT[method]
              if fnmatch.fnmatch(prop_name, pat):
                  return True
  
          return False
docs: Returns `True` if the given method was previously added as an
          observing method, either dynamically or via decorator.