[DOC] Added an example to CNNRegressor #4264

[meraldoantonio]

Reference Issues/PRs

Adds to #4264

What does this implement/fix? Explain your changes.

Added one usage example to CNNRegressor.

Does your contribution introduce a new dependency? If yes, which one?

No

What should a reviewer concentrate their feedback on?

Reviewing the example and my workflow

Did you add any tests for the change?

No

Any other comments?

No

PR checklist

For all contributions

• I've added myself to the list of contributors with any new badges I've earned :-)
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  See here for full badge reference
• Optionally, I've added myself and possibly others to the CODEOWNERS file - do this if you want to become the owner or maintainer of an estimator you added.
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• The PR title starts with either [ENH], [MNT], [DOC], or [BUG]. [BUG] - bugfix, [MNT] - CI, test framework, [ENH] - adding or improving code, [DOC] - writing or improving documentation or docstrings.

[fkiraly]

Nice, thanks!

[meraldoantonio]

Hi @fkiraly, thanks for checking the PR!
If everything is OK, could you please give me the permission to merge it?

[fkiraly]

Sure!

[meraldoantonio]

One required test failed because of invalid keras filepath, and I'm not too sure how to change this path.. Could someone please help me on this?

This is the error:

ValueError: Invalid filepath extension for saving. Please add either a `.keras` extension for the native Keras format (recommended) or a `.h5` extension. Use `tf.saved_model.save()` if you want to export a SavedModel for use with TFLite/TFServing/etc. Received: filepath=/tmp/pytest-of-runner/pytest-0/popen-gw1/test_cnn_model_save_and_load_p0/model/model/keras.

[fkiraly]

That's unrelated, it is coming from tensorflow recent release being incompatible with the adapter, see here #6094 - nothing about your changes.