cannot import name '_validate_lengths'

/usr/local/lib/python3.6/dist-packages/skimage/util/arraycrop.py

import numpy as np
from numpy.lib.arraypad import _validate_lengths

改成下面的

import numpy as np
from distutils.version import LooseVersion as Version
old_numpy = Version(np.__version__) < Version('1.16')
if old_numpy:
    from numpy.lib.arraypad import _validate_lengths
else:
    from numpy.lib.arraypad import _as_pairs