fix import order for attacks.py
from abc import ABCMeta
+import collections
+import warnings
+
import numpy as np
from six.moves import xrange
-import warnings
-import collections
import cleverhans.utils as utils
from cleverhans.model import Model, CallableModelWrapper
-from distutils.version import LooseVersion
from cleverhans.compat import reduce_sum, reduce_mean
from cleverhans.compat import reduce_max, reduce_min
from cleverhans.compat import reduce_any
