Plugin/mlflow custom flavor

[skrawcz]

Adds the ability to save/load custom flavors for MLFlow.

Current features

Currently, the MLFlow plugin would allow for 2 main patterns.

to.mlflow(...)  # infer the flavor

to.mlflow(..., flavor="sklearn")  # mlflow supported flavor 

^Note that this should support the pyfunc flavor, which is a convenient way to create custom estimators (MLFlow reference)

Solution

The most straight forward solution is to allow flavor to receive the Python module defining the custom flavor.

import custom_flavor
to.mlflow(..., flavor=custom_flavor)

consequently, this would also work

import mlflow
to.mlflow(..., flavor=mlflow.sklearn)

Changes

• mlflow data saver and data loaders

How I tested this

• via tests

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.