* fixed a problem with multi index caused by the default value of groupkey
* modify group_key default value
* limit pandas verion
* format with black
* fix docs error
* fix docs error
* fixed bugs caused by pandas upgrade
* remove needless code
* reformat with black
* limit version & add docs
* Intermediate version
* Fix yaml template & Successfully run rolling
* Be compatible with benchmark
* Get same results with previous linear model
* Black formatting
* Update black
* Update the placeholder mechanism
* Update CI
* Update CI
* Upgrade Black
* Fix CI and simplify code
* Fix CI
* Move the data processing caching mechanism into utils.
* Adjusting DDG-DA
* Organize import