[SciPy-User] Optimization on the subspace of a domain

Hello there, As I am learning how to do minimization using SciPy, I wonder if I can do the minimization just on a (proper) subspace of the domain of a function. For instance, if I have a multivariate function f(x,y,z), can I ask SciPy to find a minimum by changing only x and y and keeping z fixed? It would work if I define a new function: f(x,y,z_0) = h(x,y) for a given z_0, but I wonder if there is an option for doing that without defining another function. Thanks.