def at_talk(self, caller):
        """
        Called when obj targeted by a talk command.
        """
        conversation = {}
        exec(self.db.conversation)

        EvMenu(
            caller,
            conversation,
            startnode="node1",
            persistent=False,
            cmd_on_exit=None,
        )

----------------------------------------------

lab_aide = create_object(characters_trainers.Trainer, key="Lab Aide",
                         aliases=["Aide"], location=laboratory)

lab_aide.db.conversation = """
def node1(caller):
    text = "I study POKEMON as PROF.OAK'S AIDE."
    options = None
    return utils_text.nobordertext(text, "Lab Aide"), options

conversation = {"node1": node1}
"""

------------------------------------------------

Results in:

Traceback (most recent call last):
  File "/home/ubuntu/environment/evennia/evennia/commands/cmdhandler.py", line 631, in _run_command
    ret = cmd.func()
  File "./features/NPCs.py", line 59, in func
    target.at_talk(caller)
  File "./features/NPCs.py", line 97, in at_talk
    cmd_on_exit=None,
  File "/home/ubuntu/environment/evennia/evennia/utils/evmenu.py", line 445, in __init__
    raise EvMenuError("Start node '%s' not in menu tree!" % startnode)
evennia.utils.evmenu.EvMenuError: Start node 'node1' not in menu tree!

An untrapped error occurred.
(Traceback was logged 19-10-15 12:33:35).