code: def _is_national_number_suffix_of_other(numobj1, numobj2):
      
      nn1 = str(numobj1.national_number)
      nn2 = str(numobj2.national_number)
      # Note that endswith returns True if the numbers are equal.
      return nn1.endswith(nn2) or nn2.endswith(nn1)
docs: Returns true when one national number is the suffix of the other or both
      are the same.