code: def _is_2D_matrix(matrix):
      """Checks to see if a ndarray is 2D or a list of lists is 2D"""
      return (
          isinstance(matrix[0], list)
          and _rectangular(matrix)
          and not isinstance(matrix[0][0], list)
      ) or (not isinstance(matrix, list) and matrix.shape == 2)
  
file_path: mxboard/python/mxboard/utils.py
imports: from __future__ import absolute_import
  import os
  import logging
  import numpy
  from mxnet.ndarray import NDArray, op
  from mxnet.ndarray import ndarray
  from mxnet.context import current_context
label_desc: Use image node_id 2 for calling a global function with example usage: _is_2D_matrix(matrix) and returns: unknown