efficient calculation of nCr using sets

Choose Function

def choose(n,k):
    "efficient calculation of nCr using sets"
    
    if n < k:
        raise ValueError('n < k')
        
    n_set, k_set = set(range(1,n+1)), set(range(1,k+1))
    n_min_k_set = set(range(1,(n-k)+1))
    
    if len(n_min_k_set) < len(k_set):
        return product(list(n_set - k_set)) / product(list(n_min_k_set))
    else:
        return product(list(n_set - n_min_k_set)) / product(list(k_set))