__slots__ went missing from Template.

Lib/string.py

@@ -105,6 +105,7 @@ class _TemplateMetaclass(type):
 class Template:
     """A string class for supporting $-substitutions."""
     __metaclass__ = _TemplateMetaclass
+    __slots__ = ['template']
 
     delimiter = r'\$'
     idpattern = r'[_a-z][_a-z0-9]*'