def __init__(self, regex='.*', collections=None):
        """
        Args:
            regex(str): same as in :class:`MapGradient`.
            collections (list[str]): list of collection names
        """
        super(SummaryGradient, self).__init__(self._mapper, regex)
        self._coll = collections
def __init__ ( self , regex = '.*' , collections = None ) : super ( SummaryGradient , self ) . __init__ ( self . _mapper , regex ) self . _coll = collections
Args:
            regex(str): same as in :class:`MapGradient`.
            collections (list[str]): list of collection names