from typing import Any

from sympy.core.function import Function, UndefinedFunction

_x = ...

class Ynm(Function):
    @classmethod
    def eval(cls, n, m, theta, phi) -> type[UndefinedFunction] | None: ...
    def fdiff(self, argindex=...): ...
    def as_real_imag(self, deep=..., **hints) -> tuple[Any, Any]: ...

def Ynm_c(n, m, theta, phi) -> type[UndefinedFunction]: ...

class Znm(Function):
    @classmethod
    def eval(cls, n, m, theta, phi) -> type[UndefinedFunction] | None: ...