code: def remove_duplicates(self, ws):
          
          for analysis in ws.objectValues():
              if IDuplicateAnalysis.providedBy(analysis) \
                      and analysis.getAnalysis().UID() == self.UID():
                  ws.removeAnalysis(analysis)
docs: When this analysis is unassigned from a worksheet, this function
          is responsible for deleting DuplicateAnalysis objects from the ws.