Python - Problema Numpy o for :(

def grad_check(X,y,Theta, epsilon_,lambda_):

    grad_aprox = np.ones(np.size(Theta))

    for i in range(len(Theta)):

        ma_theta = Theta

        ma_theta[i] = ma_theta[i] + epsilon_

        meno_theta = Theta

        meno_theta[i] = meno_theta[i] - epsilon_

        grad_aprox[i] = ((cost_function(X,y,ma_theta, lambda_) - cost_function(X,y,meno_theta,lambda_)) / (2 * epsilon_))

    return grad_aprox