def group_by(self, *args):
        """
        Indica los campos para agrupación
        """
        if len(args) == 1:
            self.raw_fields_group = args[0].split(',')
        else:
            self.raw_fields_group = list(args)
        return self
def group_by ( self , * args ) : if len ( args ) == 1 : self . raw_fields_group = args [ 0 ] . split ( ',' ) else : self . raw_fields_group = list ( args ) return self
Indica los campos para agrupación