(self, value)
| 733 | self.max = None |
| 734 | |
| 735 | def add(self, value): |
| 736 | super().add(value) |
| 737 | self.min = value if self.min is None else min(self.min, value) |
| 738 | self.max = value if self.max is None else max(self.max, value) |
| 739 | |
| 740 | def diff(self): |
| 741 | return 0 if self.min is None or self.max is None else self.max - self.min |