class_docstr: Select index of an array element from a given axis.
code: def __init__(self, axis=None):
      if axis is None:
          self.axis = None
      elif isinstance(axis, six.integer_types):
          self.axis = axis
      else:
          raise TypeError("None or int are required")
  
imports: import numpy
  import six
  from chainer import backend
  from chainer import function_node
  import chainer.functions
  import chainer.utils
  from chainer.utils import type_check
  import chainerx
label_desc: Use image node_id 1 to create a new IndexSelectorBase object from inherited base classes: function_node with example: obj = IndexSelectorBase(axis)