foundry-fork-db can not pull delegate implementation code

[boying52]

the curveV1's CurveStableSwapNG pools, if I use revm+foundry-fork-db to simulation and should faild,because it's get_dy code is
@view
@external
def get_dy(i: int128, j: int128, dx: uint256) -> uint256:
"""
@notice Calculate the current output dy given input dx
@dev Index values can be found via the coins public getter method
@param i Index value for the coin to send
@param j Index value of the coin to receive
@param dx Amount of i being exchanged
@return Amount of j predicted
"""
return StableSwapViews(factory.views_implementation()).get_dy(i, j, dx, self)

the return StableSwapViews(factory.views_implementation()).get_dy(i, j, dx, self) is key to faild, foundry-fork-db can not download them