python (3.11.7)
1 from setuptools.extern.more_itertools import consume # noqa: F401
2
3
4 # copied from jaraco.itertools 6.1
5 def ensure_unique(iterable, key=lambda x: x):
6 """
7 Wrap an iterable to raise a ValueError if non-unique values are encountered.
8
9 >>> list(ensure_unique('abc'))
10 ['a', 'b', 'c']
11 >>> consume(ensure_unique('abca'))
12 Traceback (most recent call last):
13 ...
14 ValueError: Duplicate element 'a' encountered.
15 """
16 seen = set()
17 seen_add = seen.add
18 for element in iterable:
19 k = key(element)
20 if k in seen:
21 raise ValueError(f"Duplicate element {element!r} encountered.")
22 seen_add(k)
23 yield element
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