* 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 yaml config

* Add yaml for flatten_contiguous_range_op

* Remove h_sigmoid yaml

* Fix CI errors

* Fix code format

* Fix flatten OP errors

* Fix conflicts

* Fix CI errors

* Remove flatten_contiguous_range OP

* Remove redundant code

* Fix typos

* fix uncontrolled randomness of op

* fix bugs