Find Mesh Cell of Point

Hello dear all…

I am using fenics 2019.1.0. I want to use refine function to make mesh more fine close to certain point. In documentation, it says that refine function needs cell or cells where I want to make mesh fine.

I am having two questions. First, what data type is ‘cell’ stored as? Then, what is most efficient way to get cell for a specific point?

I think I have solution given here refine