human
Solve the following python programming problem given the following code:
def ssgplvm_simulation_linear() : 
    import numpy as np 
    import GPy 
    (N, D, Q) = (1000, 20, 5) 
    pi = 0.2 
    def sample_X(Q, pi) : 
        x = np.empty (Q) 
        dies = np.random.rand (Q) 
        for q in range (Q) : 
            if (dies [q] < pi) : 
                x [q] = np.random.randn () 
else : 
                x [q] = 0.0 
return x 
Y = np.empty ((N, D)) 
    X = np.empty ((N, w)) 
    for n in range (N) : 
        X [n] = sample_X (Q, pi) 
        w = np.random.randn (D, Q) 
        Y [n] = np.dot (w, X [n]) 

    
    

    Fix the buggy line: X = np.empty ((N, w))
assistant
#Here is Python code to fix the buggy line: X = np.

X = np.empty ((N, Q))