code: def __init__(self, canvas, num):
      backend_bases.FigureManagerBase.__init__(self, canvas, num)
  
      self.web_sockets = set()
  
      self.toolbar = self._get_toolbar(canvas)
  
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 1 to create a new FigureManagerWebAgg object from inherited base classes: backend_bases with example: obj = FigureManagerWebAgg(canvas, num)