closes issue18042 -- a `unique` decorator is added to enum.py
The docs also clarify the 'Interesting Example' duplicate-free enum is for
demonstration purposes.
diff --git a/Lib/enum.py b/Lib/enum.py
index 775489b..38d95c5 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -4,7 +4,7 @@
from collections import OrderedDict
from types import MappingProxyType
-__all__ = ['Enum', 'IntEnum']
+__all__ = ['Enum', 'IntEnum', 'unique']
class _RouteClassAttributeToGetattr:
@@ -463,3 +463,17 @@
class IntEnum(int, Enum):
"""Enum where members are also (and must be) ints"""
+
+
+def unique(enumeration):
+ """Class decorator for enumerations ensuring unique member values."""
+ duplicates = []
+ for name, member in enumeration.__members__.items():
+ if name != member.name:
+ duplicates.append((name, member.name))
+ if duplicates:
+ alias_details = ', '.join(
+ ["%s -> %s" % (alias, name) for (alias, name) in duplicates])
+ raise ValueError('duplicate values found in %r: %s' %
+ (enumeration, alias_details))
+ return enumeration