code: def plot(self, threshold=None, **kwargs):
          
          try:
              # Works under matplotlib 3.
              pyplot.bar(x=self.ma.delays+.5, height=self.response,
                         width=1., fill=False, **kwargs)
          except TypeError:   # pragma: no cover
              # Works under matplotlib 2.
              pyplot.bar(left=self.ma.delays+.5, height=self.response,
                         width=1., fill=False, **kwargs)
          pyplot.xlabel('time')
          pyplot.ylabel('response')
          if threshold is not None:
              cumsum = numpy.cumsum(self.response)
              idx = numpy.where(cumsum > threshold*cumsum[-1])[0][0]
              pyplot.xlim(0., idx)
docs: Barplot of the ARMA response.