tesselate_polygon was or is a helper class from the geometry utils provided with the blender python API. Maybe it’s name changed. It’s purpose is to return a vector/face list that fills any number of vertices. I used this to create the faces of an area surface from the contour vertices.
When I import the osm file, only show me a Empty plain axes, somebody knows why?
I got that as well. Except, I wasn’t looking at what I thought I was looking at. 
Select the empty and scale it right down a LOT, then you see the geometry come into view, the original import is HUGE and can go beyond the clipping planes. I also then added a plane, joined everything but the empty to that and got rid of the empty, not needed, but just so I could see the object as a mesh and not a parent empty. 
if you select all in the scene and check the faces/tris count, you can see there is data there, but yep, took me a while to figure that one out.