When using the 'n_values' parameter, the code works as expected and I get the deprecation warning. However, when the code is changed to what's suggested in deprecation warning, getting a ValueError.
This works:

from sklearn.preprocessing import OneHotEncoder
ohe = OneHotEncoder(n_values= 8,sparse = False)
o = ohe.fit_transform(np.array([[3, 5, 1]]))
o = o.reshape(1,3,8)
print(o)

[[[0. 0. 0. 1. 0. 0. 0. 0.] [0. 0. 0. 0. 0. 1. 0. 0.] [0. 1. 0. 0. 0. 0. 0. 0.]]] C:\Anaconda3\lib\site-packages\sklearn\preprocessing\_encoders.py:331: DeprecationWarning: Passing 'n_values' is deprecated in version 0.20 and will be removed in 0.22. You can use the 'categories' keyword instead. 'n_values=n' corresponds to 'categories=[range(n)]'. warnings.warn(msg, DeprecationWarning)

When I remove the n_values with categories = [range(n)] and run code as below, I get the error:

from sklearn.preprocessing import OneHotEncoder
ohe = OneHotEncoder(categories = [range(8)],sparse = False)
o = ohe.fit_transform(np.array([[3, 5, 1]]))
o = o.reshape(1,3,8)
print(o)

``ValueError Traceback (most recent call last)
in
2 import pandas as pd
3 ohe = OneHotEncoder(categories = [range(8)],sparse = False)
----> 4 o = ohe.fit_transform(np.array([[3, 5, 1]]))
5 # pd.get_dummies(np.array([3, 5, 1]))
6 o.reshape(1,3,8)

C:\Anaconda3\lib\site-packages\sklearn\preprocessing_encoders.py in fit_transform(self, X, y)
516 self._categorical_features, copy=True)
517 else:
--> 518 return self.fit(X).transform(X)
519
520 def _legacy_transform(self, X):

C:\Anaconda3\lib\site-packages\sklearn\preprocessing_encoders.py in fit(self, X, y)
427 return self
428 else:
--> 429 self._fit(X, handle_unknown=self.handle_unknown)
430 return self
431

C:\Anaconda3\lib\site-packages\sklearn\preprocessing_encoders.py in _fit(self, X, handle_unknown)
70 "supported for numerical categories")
71 if len(self._categories) != n_features:
---> 72 raise ValueError("Shape mismatch: if n_values is an array,"
73 " it has to be of shape (n_features,).")
74

ValueError: Shape mismatch: if n_values is an array, it has to be of shape (n_features,).``

Is this a usage error or a bug?

System:
python: 3.7.1 | packaged by conda-forge | (default, Nov 13 2018, 19:01:41) [MSC v.1900 64 bit (AMD64)]
executable: C:\Anaconda3\python.exe
machine: Windows-10-10.0.16299-SP0

BLAS:
macros:
lib_dirs:
cblas_libs: cblas

Python deps:
pip: 18.1
setuptools: 40.6.3
sklearn: 0.20.3
numpy: 1.15.4
scipy: 1.1.0
Cython: 0.29.2
pandas: 0.23.4