| """Utilities for defining models | |
| """ | |
| # The following comment should be removed at some point in the future. | |
| # mypy: disallow-untyped-defs=False | |
| import operator | |
| class KeyBasedCompareMixin(object): | |
| """Provides comparison capabilities that is based on a key | |
| """ | |
| def __init__(self, key, defining_class): | |
| self._compare_key = key | |
| self._defining_class = defining_class | |
| def __hash__(self): | |
| return hash(self._compare_key) | |
| def __lt__(self, other): | |
| return self._compare(other, operator.__lt__) | |
| def __le__(self, other): | |
| return self._compare(other, operator.__le__) | |
| def __gt__(self, other): | |
| return self._compare(other, operator.__gt__) | |
| def __ge__(self, other): | |
| return self._compare(other, operator.__ge__) | |
| def __eq__(self, other): | |
| return self._compare(other, operator.__eq__) | |
| def __ne__(self, other): | |
| return self._compare(other, operator.__ne__) | |
| def _compare(self, other, method): | |
| if not isinstance(other, self._defining_class): | |
| return NotImplemented | |
| return method(self._compare_key, other._compare_key) | |