More docs, error messages, and tests
diff --git a/Lib/collections.py b/Lib/collections.py
index fbc00d1..0feda0a 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -2,6 +2,7 @@
from _collections import deque, defaultdict
from operator import itemgetter as _itemgetter
+from keyword import iskeyword as _iskeyword
import sys as _sys
def named_tuple(typename, field_names, verbose=False):
@@ -35,6 +36,8 @@
for name in (typename,) + field_names:
if not name.replace('_', '').isalnum():
raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name)
+ if _iskeyword(name):
+ raise ValueError('Type names and field names cannot be a keyword: %r' % name)
if name[0].isdigit():
raise ValueError('Type names and field names cannot start with a number: %r' % name)
seen_names = set()