docs: def adjustPlot(self, readsAx):
          """
          Add a horizontal line to the plotted reads if we're plotting e-values
          and a zero e-value was found.
  
          @param readsAx: A Matplotlib sub-plot instance, as returned by
              matplotlib.pyplot.subplot.
          """
          # If we're using bit scores, there's nothing to do.
          if self.scoreClass is HigherIsBetterScore:
              return
  
          if self._zeroEValueFound:
              readsAx.axhline(y=self._maxConvertedEValue + 0.5, color='#cccccc',
                              linewidth=0.5)