from sympy.abc import a, b, c, d, e, f, s
from sympy.physics.control.lti import TransferFunction
from spb import plot_nyquist
tf = TransferFunction(a * s**2 + b * s + c, d**2 * s**2 + e * s + f, s)
plot_nyquist(
    tf,
    params={
        a: (2, 0, 10),
        b: (5, 0, 10),
        c: (1, 0, 10),
        d: (1, 0, 10),
        e: (2, 0, 10),
        f: (3, 0, 10),
    },
    m_circles=False,
    xlim=(-1, 4), ylim=(-2.5, 2.5), aspect="equal"
)