code: def process_image(self, padded_src, dpi):
      raise NotImplementedError("Should be overridden by subclasses")
  
imports: import matplotlib.pyplot
  import numpy
  from matplotlib.artist import Artist
  import matplotlib.cm
  from matplotlib.colors import LightSource
  import matplotlib.transforms
label_desc: Use image node_id 2 for calling the BaseFilter obj's underlying member method code with example usage: obj.process_image(padded_src, dpi) without return types