class_docstr: Cumulative sum of array elements over a given axis.
code: def __init__(self, axis=None):
      if isinstance(axis, six.integer_types) or axis is None:
          self.axis = axis
      else:
          raise TypeError("axis must be int or None")
  
file_path: chainer/chainer/functions/math/cumsum.py
imports: import six
  from chainer import backend
  from chainer import function_node
  from chainer.functions.array import flip
  from chainer.utils import type_check
label_desc: Use image node_id 1 to create a new Cumsum object from inherited base classes: function_node with example: obj = Cumsum(axis)