fix character index in ExtendedInterpolation's exception message
diff --git a/Lib/configparser.py b/Lib/configparser.py
index c7bee6b..6c5aa49 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -456,7 +456,7 @@
tmp_value = self._KEYCRE.sub('', tmp_value) # valid syntax
if '$' in tmp_value:
raise ValueError("invalid interpolation syntax in %r at "
- "position %d" % (value, tmp_value.find('%')))
+ "position %d" % (value, tmp_value.find('$')))
return value
def _interpolate_some(self, parser, option, accum, rest, section, map,