venv/lib/python3.11/site-packages/setuptools/_itertools.py

   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