code: def is_empty(self):
          
          if(((self.channels == []) and (not self.shape == (0, 0))) or
             ((not self.channels == []) and (self.shape == (0, 0)))):
              raise RuntimeError("Channels-shape mismatch.")
          return self.channels == [] and self.shape == (0, 0)
docs: Checks for an empty image.