code: def showDiffResults(self):
          
          try:
              oldWarnings = self.parseWarnings(self._readDiffFile())
          except:
              sys.stderr.write(self.errorResultRead % self.diffOption)
              return 1
  
          newWarnings = self.parseWarnings(self.streamForDiff.getvalue())
  
          diffWarnings = self.generateDiff(oldWarnings, newWarnings)
  
          if diffWarnings:
              diffResult = self.formatWarnings(diffWarnings)
              self.outputStream.write(diffResult + "\n")
              return len(diffWarnings)
          else:
              return 0
docs: Show results when diff option on.