def METHOD_NAME(self):
    self.dff_insts={}
    for row in range(self.rows):
        for col in range(self.columns):
            name = "Xdff_r{0}_c{1}".format(row,col)
            self.dff_insts[row,col]=self.add_inst(name=name,
                                                  mod=self.dff)
            self.connect_inst([self.get_din_name(row,col),
                               self.get_dout_name(row,col),
                               self.get_dout_bar_name(row,col),
                               "clk",
                               "vdd",
                               "gnd"])