PaddlePaddle 2.x 无法增量训练

PaddlePaddle 2.x以后的版本没有办法进行增量训练吗？训练时候会出现下面的报错：
`AssertionError: In PaddlePaddle 2.x, we turn on dynamic graph mode by default, and 'data()' is only supported in static graph mode. So if you want to use this api, please call 'paddle.enable_static()' before this api to enter static graph mode.`

Start by reproducing the incremental-training flow that triggers the reported PaddlePaddle 2.x assertion, then inspect the surrounding training entry point and how static or dynamic graph mode is selected. Done means establishing whether incremental training is supported in this version and documenting or correcting the compatible path, with a reproducible verification.

Written by the indexing model from the issue text.