cannot use minpy.numpy.newaxis?

[Grayscale-cc]

import minpy.numpy as np
a = np.zeros((3,3))
b = a[:, :, np.newaxis]

The following error occurred when I executed the above code:
b = a[:, :, np.newaxis]
File "/home/ai/anaconda3/envs/mask/lib/python3.6/site-packages/minpy/array.py", line 440, in getitem
np_index = tuple(_make_numpy_index(i) for i in index)
File "/home/ai/anaconda3/envs/mask/lib/python3.6/site-packages/minpy/array.py", line 440, in
np_index = tuple(_make_numpy_index(i) for i in index)
File "/home/ai/anaconda3/envs/mask/lib/python3.6/site-packages/minpy/array.py", line 493, in _make_numpy_index
np_index = wrap(raw_index).asnumpy()
AttributeError: 'NoneType' object has no attribute 'asnumpy'.

Is there no newaxis in minpy now?