code: def comparison_negative(logical_line):
      r
      match = COMPARE_NEGATIVE_REGEX.search(logical_line)
      if match:
          pos = match.start(1)
          if match.group(2) == 'in':
              yield pos, "E713 test for membership should be 'not in'"
          else:
              yield pos, "E714 test for object identity should be 'is not'"
docs: r"""Negative comparison should be done using "not in" and "is not".
  
      Okay: if x not in y:\n    pass
      Okay: assert (X in Y or X is Z)
      Okay: if not (X in Y):\n    pass
      Okay: zz = x is not y
      E713: Z = not X in Y
      E713: if not X.B in Y:\n    pass
      E714: if not X is Y:\n    pass
      E714: Z = not X.B is Y