ay of
identifying specializations of <tt class="docutils literal">bases&lt; … &gt;</tt> is to derive them all
from the same class, as an implementation detail:</p>
<pre class="literal-block">
namespace boost { namespace python {

namespace detail { struct bases_base {}; }

template &lt;class A0 = void, class A1 = void, class A2 = void <em>…</em> &gt;
struct bases <strong>: detail::bases_base</strong>
{};

}}
</pre>
<!-- @example.replace_emphasis('') -->
<!-- @example.prepend('''
#include <boost/paramete