Avoid deprecation warning from sklearn.externals.six

[ksbeattie]

The changes here should avoid the deprecation warnings from sklearn about its internal six module being deprecated in favor of the "official" six module:

$ python -c "import mlrose"
/Users/ksb/opt/anaconda3/envs/ccsi-foqus/lib/python3.7/site-packages/sklearn/externals/six.py:31: FutureWarning: The module is deprecated in version 0.21 and will be removed in version 0.23 since we've dropped support for Python 2.7. Please rely on the official version of six (https://pypi.org/project/six/).
  "(https://pypi.org/project/six/).", FutureWarning)

I also changed the name used to identify scikit-learn as a requirement to (what I understand to be) the more correct name scikit-learn which avoids the "alias" package sklearn-0.0 from getting installed.

All the tests run by ./test/test.sh still pass with this change, so hopefully this is correct. If not, hopefully this is a hint in the direction on how to avoid the deprecation warning.

[ksbeattie]

@gkhayes, any chance you could take a look at this?

[JohnStratoudakis]

I am getting an error when trying to use mlrose as mentioned above:

→ python3.7 -c "import mlrose"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/mlrose/__init__.py", line 12, in <module>
    from .neural import NeuralNetwork, LinearRegression, LogisticRegression
  File "/usr/local/lib/python3.7/site-packages/mlrose/neural.py", line 12, in <module>
    from sklearn.externals import six
ImportError: cannot import name 'six' from 'sklearn.externals' (/usr/local/lib/python3.7/site-packages/sklearn/externals/__init__.py)

And making the first change get's rid of any error occurring during import.

[ksbeattie]

It seems that scikit-learn has released 0.23.1 and removed six from their sklearn.externals module, so this warning is now an error. Hopefully mlrose will be updated soon as well?

[JohnStratoudakis]

I downgraded my scikit-learn to version 0.22 and my code is now working again. So my requirements.txt file now has:

scikit-learn==0.22

[arainboldt]

hi guys, love the package. Any plans to refactor this?

[ksbeattie]

hi guys, love the package. Any plans to refactor this?

@arainboldt, it appears that mlrose-hiive (a fork of this repo) has done this.

We've moved to using that module now.