GP evaluation speed within model

Sorry, I’m a bit confused, could you clarify a couple things? In logZ, logU and age there is *grid.range('Age'), so I’m assuming its a (2, ) shaped tuple. But then later there is

linelumsperqh = grid.predictt(grid_params)  #  calls GP grid for all observ ... 

which is from a gp object. Am I reading this right?