docs: def breakpoints( self ):
          """
          Returns a list of lines that have breakpoints for this edit.
          
          :return     [<int>, ..]
          """
          lines = []
          result = self.markerFindNext(0, self._breakpointMarker + 1)
          while ( result != -1 ):
              lines.append(result)
              result = self.markerFindNext(result + 1, self._breakpointMarker + 1)
          return lines