docs: def CheckPreviousBarline(self, staff):
          """method which checks the bar before the current for changes we need to make to it's barlines"""
          measure_before_last = self.getMeasureAtPosition(-2, staff)
          last_measure = self.getMeasureAtPosition(-1, staff)
          if last_measure is not None and measure_before_last is not None:
              bline1 = measure_before_last.GetBarline("right")
              bline2 = last_measure.GetBarline("left")
              if bline1 is not None:
                  if hasattr(bline1, "ending"):
                      if bline2 is not None:
                          if not hasattr(bline2, "ending"):
                              bline1.ending.type = "discontinue"
                      else:
                          bline1.ending.type = "discontinue"