[C++-sig] why am I getting a Boost.Python.ArgumentError?

[Tom Haynes]

When trying to called a wrapped method (getName) from python, I get
the following error:

    return self.geometry.getName()
Boost.Python.ArgumentError: Python argument types in
    Geometry.getName(Geometry)
did not match C++ signature:
    getName(gfx::Geometry {lvalue})

I don't understand why these don't match, though.  It seems to say
that the C++ signature is Geometry::getName() (which is true) ... and
that's how I'm calling it from python.  If I "print self.geometry" I
get that it is a gfx.Geometry object.

Thanks for your help.

-tom