models.py•1.33 kB
"""Utilities for defining models
"""
import operator
from typing import Any, Callable, Type
class KeyBasedCompareMixin:
"""Provides comparison capabilities that is based on a key"""
__slots__ = ["_compare_key", "_defining_class"]
def __init__(self, key, defining_class):
# type: (Any, Type[KeyBasedCompareMixin]) -> None
self._compare_key = key
self._defining_class = defining_class
def __hash__(self):
# type: () -> int
return hash(self._compare_key)
def __lt__(self, other):
# type: (Any) -> bool
return self._compare(other, operator.__lt__)
def __le__(self, other):
# type: (Any) -> bool
return self._compare(other, operator.__le__)
def __gt__(self, other):
# type: (Any) -> bool
return self._compare(other, operator.__gt__)
def __ge__(self, other):
# type: (Any) -> bool
return self._compare(other, operator.__ge__)
def __eq__(self, other):
# type: (Any) -> bool
return self._compare(other, operator.__eq__)
def _compare(self, other, method):
# type: (Any, Callable[[Any, Any], bool]) -> bool
if not isinstance(other, self._defining_class):
return NotImplemented
return method(self._compare_key, other._compare_key)