bazarr/libs/bidict/_frozen.py

51 lines
1.7 KiB
Python

# Copyright 2009-2024 Joshua Bronson. All rights reserved.
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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# (see comments in __init__.py)
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# ← Prev: _base.py Current: _frozen.py Next: _bidict.py →
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"""Provide :class:`frozenbidict`, an immutable, hashable bidirectional mapping type."""
from __future__ import annotations
import typing as t
from ._base import BidictBase
from ._typing import KT
from ._typing import VT
class frozenbidict(BidictBase[KT, VT]):
"""Immutable, hashable bidict type."""
_hash: int
if t.TYPE_CHECKING:
@property
def inverse(self) -> frozenbidict[VT, KT]: ...
@property
def inv(self) -> frozenbidict[VT, KT]: ...
def __hash__(self) -> int:
"""The hash of this bidict as determined by its items."""
if getattr(self, '_hash', None) is None:
# The following is like hash(frozenset(self.items()))
# but more memory efficient. See also: https://bugs.python.org/issue46684
self._hash = t.ItemsView(self)._hash()
return self._hash
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