[C++-sig] Translating "type()"

[Joseph Lisee]

I have a line of python code that generates a new class:

class_name = "NewClass"
NewClass = type(class_name, (object,), {})

I have tried to replicate this in Boost.Python with this:

object NewClass = class_<object>(class_name);

This give warnings about registering a to-python convert more than once. 
What is the proper way to do this, ie: Generate a new class with the given
name.

-Joe