code: def info_string(self, size=None, message='', frame=-1):
          
          info = []
          if size is not None:
              info.append('Size: {1}x{0}'.format(*size))
          elif self.size is not None:
              info.append('Size: {1}x{0}'.format(*self.size))
          if frame >= 0:
              info.append('Frame: {}'.format(frame))
          if message != '':
              info.append('{}'.format(message))
          return ' '.join(info)
docs: Returns information about the stream.
  
          Generates a string containing size, frame number, and info messages.
          Omits unnecessary information (e.g. empty messages and frame -1).
  
          This method is primarily used to update the suptitle of the plot
          figure.
  
          Returns:
              An info string.