Why is MeshClosestPoint returning none when using python, but not when using gh components?

Attached is a .gh file that demonstrates my problem

The python script is supposed to accept a mesh, define a box, and then find the closest point on the mesh to the center of that box. When i try to do this using python scripting component, the MeshClosestPoint returns "none." [This is demonstrated in the yellow panels]

Alternatively, when I do this using the given grasshopper components I get the right result [demonstrated in the green panel].

I have a feeling this has something to do with my lack of understanding of what is actually being returned when I try to access the box / center point. Never programmed in python or rhino scripting. Hopefully this is a stupid mistake. Thanks for the help!

-mike