code: def _block_format_index(index):
      """
      Convert a list of indices ``[0, 1, 2]`` into ``"arrays[0][1][2]"``.
      """
      idx_str = "".join(
          "[{}]".format(i) for i in index if i is not None
      )
      return "arrays" + idx_str
  
imports: from __future__ import division, absolute_import, print_function
  import functools
  import operator
  import types
  import warnings
  from .None import numeric
  from .None import overrides
  from .numeric import array, asanyarray, newaxis
  from .multiarray import normalize_axis_index
label_desc: Use image node_id 14 for calling a global function with example usage: _block_format_index(index) and returns: unknown