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diff --git a/Lib/collections.py b/Lib/collections.py
index 099cdd6..a234b44 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -34,7 +34,8 @@
"""
- # Parse and validate the field names
+ # Parse and validate the field names. Validation serves two purposes,
+ # generating informative error messages and preventing template injection attacks.
if isinstance(field_names, basestring):
field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas
field_names = tuple(field_names)