'Returns the discretized `StateSpace` system.
Parameters: See `cont2discrete` for details.
Returns
sys: instance of `dlti` and `StateSpace`'

def to_discrete(self, dt, method='zoh', alpha=None):

    return StateSpace(dt=dt, *cont2discrete((self.A, self.B, self.C, self.D), dt, method=method, alpha=alpha)[:(-1)])
