* base class for estimator and eventhandler

* add license

* add event handlers

* fix pylint

* improve arg check

* fix pylint

* add unit tests

#14464)

* Fixed issue where the estimator was printing beyond the dataset size for the last batch

* Added comments

* Nudge to CI

…API (#14442)

* added estimator unittests

* add more tests for estimator

* added validation logic

* added error handlers, unittests

* improve val stats

* fix pylint

* fix pylint

* update unit test

* fix tests

* fix tests

* updated metrics, val logic

* trigger ci

* trigger ci

* update metric, batch_fn error handler

* update context logic, add default metric

* add train history

* update history

* update test

* avoid calling empty methods

* remove train history object

* fix pylint

* add unit test

* fix test

* update categorize handlers

* Added RNN integration test for fit() API

* Addressed review comments: change in JenkinFile, tmp directory, ctx with condense if/else, renamed imports

* CPU test doesn't require nvidiadocker container

* Modified the structure by removing the redundant code

* added cnn intg tests for fit api

* updated cnn intg tests

* added functions for nightly test

* updated runtime_function

* updated intg tests

* updated init, datapath, refs

* added validation data

* update cpu test

* refactor code

* updated context

…upport for Gluon fit() API (#14587)

* Retrieve Batch size and Logging verbose support for Gluon fit() API

* NIT changes

* Addressed review comments: shifted the batch size code to a separate method, sentence correction

* Modified unittest

* removed redundant parameter

* Resolve CI test failure

* only support DataLoader for now, future PRs will include DataIter to DataLoader converter

* Get the number of samples from shape attribute instead of length due to low space complexity

* Simplified batch size retrieval code

* removed batch_size parameter from fit() method and fixed the tests

* Verbose exception handling

* Assigning constant to a verbose

* Modified exception message

* Resolved undefined class reference

* Addressed review comments: Modified verbose level names, docs, variable names

* Update estimator.py

* improve event handlers

* update tests

* passing weakref of estimator

* fix unit test

* fix test

* fix pylint

* fix test

* fix pylint

* move default metric logic

* combine nightly tests

* move to nightly for binaries

* update default handler

* fix pylint

* trigger ci

* trigger ci

* address comments

* add comment

* check available context

* fix bug

* change cpu check

* address comments

* update checkpoint

* test symbol save

* address comments

* add resume

* update doc and resume checkpoint

* update docs

* trigger ci

* trigger ci