code: def contains_set(self, other):
          
          if other is self:
              return True
  
          return (isinstance(other, RealNumbers) or
                  isinstance(other, Integers))
docs: Return ``True`` if ``other`` is a subset of the real numbers.
  
          Returns
          -------
          contained : bool
              ``True`` if other is an instance of `RealNumbers` or
              `Integers` False otherwise.
  
          Examples
          --------
          >>> real_numbers = RealNumbers()
          >>> real_numbers.contains_set(RealNumbers())
          True