def get_pw_constant_graph(self):
    result = VGroup()
    for left_x in range(8):
        xs = [left_x, (left_x + 1)]
        y = self.v_graph.underlying_function(left_x)
        line = Line(*[self.coords_to_point(x, y) for x in xs])
        line.set_color(self.v_graph.get_color())
        result.add(line)
    return result
def get_pw_constant_graph(self):
    result = VGroup()
    for left_x in range(8):
        xs = [left_x, (left_x + 1)]
        y = self.v_graph.underlying_function(left_x)
        line = Line(*[self.coords_to_point(x, y) for x in xs])
        line.set_color(self.v_graph.get_color())
        result.add(line)
    return result