diff options
| -rw-r--r-- | Lib/collections.py | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/Lib/collections.py b/Lib/collections.py index 242de60564..4515759b78 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -34,12 +34,15 @@ def named_tuple(typename, field_names, verbose=False): field_names = tuple(field_names) if not ''.join((typename,) + field_names).replace('_', '').isalnum(): raise ValueError('Type names and field names can only contain alphanumeric characters and underscores') - if any(name.startswith('__') and name.endswith('__') for name in field_names): - raise ValueError('Field names cannot start and end with double underscores') - if any(name[:1].isdigit() for name in field_names): - raise ValueError('Field names cannot start with a number') - if len(field_names) != len(set(field_names)): - raise ValueError('Encountered duplicate field name') + seen_names = set() + for name in field_names: + if name.startswith('__') and name.endswith('__'): + raise ValueError('Field names cannot start and end with double underscores: %s' % name) + if name[:1].isdigit(): + raise ValueError('Field names cannot start with a number: %s' % name) + if name in seen_names: + raise ValueError('Encountered duplicate field name: %s' % name) + seen_names.add(name) # Create and fill-in the class template argtxt = repr(field_names).replace("'", "")[1:-1] # tuple repr without parens or quotes |