code: def fix_e713(self, result):
          
          (line_index, _, target) = get_index_offset_contents(result,
                                                              self.source)
  
          match = COMPARE_NEGATIVE_REGEX.search(target)
          if match:
              if match.group(3) == 'in':
                  pos_start = match.start(1)
                  self.source[line_index] = '{0}{1} {2} {3} {4}'.format(
                      target[:pos_start], match.group(2), match.group(1),
                      match.group(3), target[match.end():])
docs: Fix (trivial case of) non-membership check.