code: def reset_x(self,x,copy=True):
          
          assert x.shape == self.shape
          if copy:
              self.__x = x.copy()
          else:
              self.__x = x
docs: reset self.__x private attribute
  
          Parameters
          ----------
          x : numpy.ndarray
          copy : bool
              flag to make a copy of 'x'. Defaule is True
          
          Note
          ----
          makes a copy of 'x' argument