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