docs: def mirror(self, axes='x', inplace=False):
          """
          Generates a symmetry of the Space respect global axes.
          
          :param axes: 'x', 'y', 'z', 'xy', 'xz', 'yz'...
          :type axes: str
          :param inplace: If True, the new ``pyny.Space`` is copied and 
              added to the current ``pyny.Space``. If False, it returns 
              the new ``pyny.Space``.
          :type inplace: bool        
          :returns: None, ``pyny.Space``
          """
          state = Polygon.verify
          Polygon.verify = False
          mirror = np.ones(3)
          if 'x' in axes:
              mirror *= np.array([-1, 1, 1])
          if 'y' in axes:
              mirror *= np.array([1, -1, 1])
          if 'z' in axes:
              mirror *= np.array([1, 1, -1])
          
          map_ = self.get_map()[1] * mirror
          space = self.map2pyny(map_)
          
          Polygon.verify = state
          if inplace:
              self.add_spaces(space)
              return None
          else:
              return space