Fixed -- Clarified that ValueError raised by converter.to_python() means no match.
@@ -146,7 +146,9 @@ A converter is a class that includes the following:
* A ``to_python(self, value)`` method, which handles converting the matched
string into the type that should be passed to the view function. It should
- raise ``ValueError`` if it can't convert the given value.
+ raise ``ValueError`` if it can't convert the given value. A ``ValueError`` is
+ interpreted as no match and as a consequence a 404 response is sent to the
+ user.
* A ``to_url(self, value)`` method, which handles converting the Python type
into a string to be used in the URL.
