diff --git a/index.rst b/index.rst
index c1847083a8ba953e88d30cda674df89dc054a392_aW5kZXgucnN0..03973eed23214d2ef413620f337fd03297f9ffb5_aW5kZXgucnN0 100644
--- a/index.rst
+++ b/index.rst
@@ -101,7 +101,7 @@
     >>> def encode_complex(obj):
     ...     if isinstance(obj, complex):
     ...         return [obj.real, obj.imag]
-    ...     raise TypeError(repr(o) + " is not JSON serializable")
+    ...     raise TypeError(repr(obj) + " is not JSON serializable")
     ...
     >>> json.dumps(2 + 1j, default=encode_complex)
     '[2.0, 1.0]'