e useful to have custom
    rvalue converters that convert to a "math_array" type instead of tuples.
    This is currently not implemented but is possible within the framework of
    Boost.Python V2 as it will be released in the next couple of weeks. [ed.:
    this was posted on 2002/03/10]

    <p>It would also be useful to also have "custom lvalue converters" such
    as std::vector&lt;&gt; &lt;-&gt; Python list. These converters would
    support the modification of the Python list from C++. For example: