from sympy import *
from sympy.abc import a, b, c
from spb import *
z = symbols("z")
expr = (z - 1) / (a * z**2 + b * z + c)
plot_riemann_sphere(
    expr, coloring="b", n=300,
    params={
        a: (1, -2, 2),
        b: (1, -2, 2),
        c: (2, -10, 10),
    }
)