def tf2zpk(b, a):
 (b, a) = normalize(b, a)
 b = ((b + 0.0) / a[0])
 a = ((a + 0.0) / a[0])
 k = b[0]
 b /= b[0]
 z = roots(b)
 p = roots(a)
 return (z, p, k)

def tf2zpk ( b , a ) : ( b , a ) = normalize ( b , a ) b = ( ( b + 0.0 ) / a [ 0 ] ) a = ( ( a + 0.0 ) / a [ 0 ] ) k = b [ 0 ] b /= b [ 0 ] z = roots ( b ) p = roots ( a ) return ( z , p , k )
return zero .