code: def check_xlim_change(self):
          '''check for new X bounds'''
          if self.xlim_pipe is None:
              return None
          xlim = None
          while self.xlim_pipe[0].poll():
              try:
                  xlim = self.xlim_pipe[0].recv()
              except EOFError:
                  return None
          if xlim != self.xlim:
              return xlim
          return Nonf check_xlim_change(self):
          '''check for new X bounds'''
          if self.xlim_pipe is None:
              return None
          xlim = None
          while self.xlim_pipe[0].poll():
              try:
                  xlim = self.xlim_pipe[0].recv()
              except EOFError:
                  return None
          if xlim != self.xlim:
              return xlim
          return None
docs: check for new X bounds