(self)
return self.iterate_graycode(-1)
Generates the previous Gray code ordered subset.

        Examples
        ========

        >>> from sympy.combinatorics.subsets import Subset
        >>> a = Subset([2,3,4], [1,2,3,4,5])
        >>> a.prev_gray().subset
        [2, 3, 4, 5]

        See Also
        ========
        iterate_graycode, next_gray
Generates the previous Gray code ordered subset.
Generates the previous Gray code ordered subset .
def prev_gray(self):
        """
        Generates the previous Gray code ordered subset.

        Examples
        ========

        >>> from sympy.combinatorics.subsets import Subset
        >>> a = Subset([2,3,4], [1,2,3,4,5])
        >>> a.prev_gray().subset
        [2, 3, 4, 5]

        See Also
        ========
        iterate_graycode, next_gray
        """
        return self.iterate_graycode(-1)
def prev_gray ( self ) : return self . iterate_graycode ( - 1 )