GraphMachine doesn't generate graph for NarcolepticSuperhero quickstart example - pytransitions

Question

I tried creating a Diagram using the NarcolepticSuperhero machine defined in the GitHub documentation but it only outputs this:
Steps to recreate:
Create a file named test.py, with this content:
from transitions import Machine
from transitions.extensions import GraphMachine
import random
class NarcolepticSuperhero(object):
# Define some states. Most of the time, narcoleptic superheroes are just like
# everyone else. Except for...
states = ['asleep', 'hanging out', 'hungry', 'sweaty', 'saving the world']
def __init__(self, name):
# No anonymous superheroes on my watch! Every narcoleptic superhero gets
# a name. Any name at all. SleepyMan. SlumberGirl. You get the idea.
self.name = name
# What have we accomplished today?
self.kittens_rescued = 0
# Initialize the state machine
self.machine = Machine(model=self, states=NarcolepticSuperhero.states, initial='asleep')
# Add some transitions. We could also define these using a static list of
# dictionaries, as we did with states above, and then pass the list to
# the Machine initializer as the transitions= argument.
# At some point, every superhero must rise and shine.
self.machine.add_transition(trigger='wake_up', source='asleep', dest='hanging out')
# Superheroes need to keep in shape.
self.machine.add_transition('work_out', 'hanging out', 'hungry')
# Those calories won't replenish themselves!
self.machine.add_transition('eat', 'hungry', 'hanging out')
# Superheroes are always on call. ALWAYS. But they're not always
# dressed in work-appropriate clothing.
self.machine.add_transition('distress_call', '*', 'saving the world',
before='change_into_super_secret_costume')
# When they get off work, they're all sweaty and disgusting. But before
# they do anything else, they have to meticulously log their latest
# escapades. Because the legal department says so.
self.machine.add_transition('complete_mission', 'saving the world', 'sweaty',
after='update_journal')
# Sweat is a disorder that can be remedied with water.
# Unless you've had a particularly long day, in which case... bed time!
self.machine.add_transition('clean_up', 'sweaty', 'asleep', conditions=['is_exhausted'])
self.machine.add_transition('clean_up', 'sweaty', 'hanging out')
# Our NarcolepticSuperhero can fall asleep at pretty much any time.
self.machine.add_transition('nap', '*', 'asleep')
def update_journal(self):
""" Dear Diary, today I saved Mr. Whiskers. Again. """
self.kittens_rescued += 1
#property
def is_exhausted(self):
""" Basically a coin toss. """
return random.random() < 0.5
def change_into_super_secret_costume(self):
print("Beauty, eh?")
batman = NarcolepticSuperhero("Batman")
batman.wake_up()
batman.state
machine = GraphMachine(model=batman)
batman.get_graph().draw("test.png", prog='dot')
Install the requirements (Ubuntu 20.10, I tested on it's docker image) and run the script:
$ apt install graphviz graphviz-dev
$ pip3 install transitions graphviz pygraphviz
$ python3 test.py
Check the generated image

Answer 1

You are instantiating a GraphMachine without any states and transitions here:
machine = GraphMachine(model=batman)
You basically reuse NarcolepticSuperhero as a model for that new machine but what you should do instead is changing the NarcolepticSuperhero's machine into a GraphMachine:
# Initialize the state machine
self.machine = GraphMachine(model=self, states=NarcolepticSuperhero.states, initial='asleep')
# [...]
batman.state
# this is not required anymore
# machine = GraphMachine(model=batman)
batman.get_graph().draw("test.png", prog='dot')