* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

[CodeStyle][NPU] use np.testing.assert_allclose instead of self.assertTrue(np.allclose(...)) (part 1) (#44988)

* autofix

* try resolve precision issues

* revert some changes

* clean some `err_msg`

* 0.0001 -> 1e-4

* update commented assert code

* try to fix some shape errors

* `numpy` -> `np`

* empty commit, trigger kunlun ci, test=kunlun

* empty commit, retrigger kunlun ci, test=kunlun

* empty commit, trigger kunlun ci, try fix npu memcpy_h2d, test=kunlun

* try fix npu import error, test=kunlun

* 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

* Update __init__.py

* Update math.py

* Create test_nanmean_api.py

* Update __init__.py

* Update __init__.py

* Update math.py

* Update test_nanmean_api.py

* Update __init__.py

* Update math.py

* Update test_nanmean_api.py

* Update test_nanmean_api.py

* Update test_nanmean_api.py

* Update math.py

* Update test_nanmean_api.py

* Update math.py

Update the nanmean example code

* Update math.py

* Update math.py

* Update math.py

Remove redundant code in nanmean

* Update math.py

change default keepdim = False

* Update test_nanmean_api.py

add nan into self.x

* Update test_nanmean_api.py

rerun CI check

* Update test_nanmean_api.py

* update code of nanmean in python/paddle/tensor/math.py and test_nanmean_api.py

* Update test_nanmean_api.py

update code format

* Update test_nanmean_api.py

update code format

* Update test_nanmean_api.py

add check grad code.

* Update math.py

update nanmean's describe of Args x

* Update test_nanmean_api.py

update format and release the test_case(self.x, keepdim=True) in check grad code.

* Update test_nanmean_api.py

Update gradient checking method

* Update test_nanmean_api.py

update code format

* Update test_nanmean_api.py 

Update code format and copyright in test_nanmean_api.py

* Update math.py

update arguments describe and code example

* Update math.py

修改了nanmean的axis参数的文档描述。

* Update math.py

updata nanmean's sample code (:name: code-example1)

* Update math.py

修改nanmean的example code 错误

* Update math.py

update example code

* Update math.py

update example code of nanmean