Setting Cell Regions

Hello all! I am modeling a subcritical pile of graphite bricks with aluminum cladding. I have a .csv file that is reading the centers of each bricks and I keep getting a TypeError: Unable to set “cell region” to “<RectangularParallelepiped at 0x7d160a279240>” which is not of type “Region”. I’m not sure why I am getting this error

Any help will be appreciated, thank you.

openmc.model.RectangularParallelepiped — OpenMC Documentation

RectangularParallelepiped is not a region, it is a surface. You will need to define the graphite_brick_region as being inside the surfaces.