exec?

test.py

import traceback

source = '''
def self():

   def test():
       assert False

   test()
'''


def aaa():

    env = {}

    exec source in env

    env['self']()


def bbb():

    exec source

    self()

try:
    aaa()
except:
    traceback.print_exc()
    
try:
    bbb()
except:
    traceback.print_exc()