demo.py

import taichi as ti
ti.init()

# you must make sure the func body here works both in python and taichi scope.
def f():
    a = 0
    for i in range(10):
        a += i
    print(a)

func_f = ti.func(f)
ker_f = ti.kernel(f)
ker_f()

@ti.kernel
def test():
    func_f()

test()