human
Solve the following python programming problem given the following code:
def _representing_matrices(basis, G, ring) : 
    '
    Compute the matrices corresponding to the linear maps `m \\mapsto
    x_i m` for all variables `x_i`.
    ' 
    domain = ring.domain 
    u = (domain.ngens - 1) 
    def var(i) : 
        return tuple (((([0] * i) + [1]) + ([0] * (u - i)))) 
def representing_matrix(m) : 
        M = [([domain.zero] * len (basis)) for _ in range (len (basis))] 
        for (i, v) in enumerate (basis) : 
            r = ring.term_new (monomial_mul (m, v), domain.one).rem (G) 
            for (monom, coeff) in r.terms () : 
                j = basis.index (monom) 
                M [j] [i] = coeff 
return M 
return [representing_matrix (var (i)) for i in range ((u + 1))] 

    
    

    Fix the buggy line: u = (domain.ngens - 1)
assistant
#Here is Python code to fix the buggy line: u = (domain.

u = (ring.ngens - 1)