* find relevant testcase

* remove with_data_parallel

* trigger CI

* do not apply ParameterServerGraphOptimizer

* remove useless optimizer

* remove with_data_parallel in test_dist_base

* fix test_fleet_base_3

* only reserve changes for GraphExecutionOptimizer

* fix bug

* fix test_minst_dgc_nccl

* fix typo

* fix test_dist_mnist_gradient_merge

* rm TestDistMnistNCCL2DGCMultiCards

* fix optimizer conflicts

* fix dist_mnist

* fix test_dist_hapi

* delete test_fleet_graph_execution_meta_optimizer & test_fleet_graph_executor

* temporally not delete unittest

* fix unittests

* fix ci

* recover prune in python/paddle/hapi/model.py

* isort all files

* revert conflicting files

* revert conflicting files

* revert conflicting files

* [CodeStyle][py2][U008] remove unnecessary args in `super()`

* remove remained args

* revert changes in test_pylayer_op

* Revert "revert changes in test_pylayer_op"

This reverts commit ff185a9ae738afac3b0264f61bde6c6b7f72e7c4.

* revert some changes in example code

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* add adaptivelsgd

* Todo fix the code to avoid the conflict.

* parameter_server_optimizer support auto_strategy

* add auto parallel L1 implementation
test=develop

* fix api document

* consider the combination of different strategies to work together

* add check approval
test=develop

* move paddle.fleet to paddle.distributed.fleet