Update abc import for backwards compatibility
@@ -17,7 +17,10 @@ from __future__ import division, unicode_literals
import numpy as np
import re
from abc import ABCMeta, abstractmethod
+try:
from collections import MutableSequence
+except ImportError:
+ from collections.abc import MutableSequence
from copy import deepcopy
# pylint: disable=W0622
from operator import add, mul, pow, sub, iadd, imul, ipow, isub
