code: def __init__(self, *args, **kwargs):
      backend_agg.FigureCanvasAgg.__init__(self, *args, **kwargs)
  
      # Set to True when the renderer contains data that is newer
      # than the PNG buffer.
      self._png_is_old = True
  
      # Set to True by the `refresh` message so that the next frame
      # sent to the clients will be a full frame.
      self._force_full = True
  
      # Store the current image mode so that at any point, clients can
      # request the information. This should be changed by calling
      # self.set_image_mode(mode) so that the notification can be given
      # to the connected clients.
      self._current_image_mode = "full"
  
      # Store the DPI ratio of the browser.  This is the scaling that
      # occurs automatically for all images on a HiDPI display.
      self._dpi_ratio = 1
  
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 FigureCanvasWebAggCore object from inherited base classes: backend_agg with example: obj = FigureCanvasWebAggCore()