docstr: Set the image mode for any subsequent images which will be sent
  to the clients. The modes may currently be either 'full' or 'diff'.
  
  Note: diff images may not contain transparency, therefore upon
  draw this mode may be changed if the resulting image has any
  transparent component.
code: def set_image_mode(self, mode):
      """
      Set the image mode for any subsequent images which will be sent
      to the clients. The modes may currently be either 'full' or 'diff'.
  
      Note: diff images may not contain transparency, therefore upon
      draw this mode may be changed if the resulting image has any
      transparent component.
  
      """
      if mode not in ["full", "diff"]:
          raise ValueError("image mode must be either full or diff.")
      if self._current_image_mode != mode:
          self._current_image_mode = mode
          self.handle_send_image_mode(None)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import datetime
  import io
  import json
  import os
  import warnings
  import numpy
  import tornado
  from matplotlib.backends import backend_agg
  from matplotlib.backend_bases import _Backend
  from matplotlib import backend_bases
  from matplotlib import _png
label_desc: Use image node_id 5 for calling the FigureCanvasWebAggCore obj's underlying member method code with example usage: obj.set_image_mode(mode) without return types