Pygaze dummy mode not working (even with code from the book)

Whenever I try to test things out in dummy mode--even when I try using code straight from the pygaze creator's book--I get this error:

I've tried just about every permutation of DUMMYMODE=True, TRACKERTYPE="dummy", and TRACKERTYPE="dumbdummy". I've tried setting trackertype to Tobii with dummymode=True. And yet it always seems to try to call eyelink. I've tried looking through the pygaze documentation in case the functions need updating (since the book is from 2016), but I haven't found anything.

By the way, I'm doing this using psychopy coder as my shell (haven't tried using builder at all). All the other code from the book has worked great within psychopy.

Please let me know if me posting the whole traceback would be helpful--its long. As for what I'm trying to do with my own experiment, I'm trying to test a saccade-contingent paradigm with my cursor. But of course the first step is to getting it to run in dummymode at all.

Any help would be much appreciated!

Here's the full code I have (copied straight from the book):

constants.py:

import os
# The DISPTYPE can be either ‘pygame’ or ‘psychopy’
DISPTYPE = 'pygame'

# The DISPSIZE should match your monitor’s resolution!
DISPSIZE = (1920, 1080)
# Set the TRACKERTYPE to the brand you use
TRACKERTYPE = 'dummy'
# DUMMYMODE should be True if no tracker is attached
DUMMYMODE = True
# Foreground colour set to white
FGC = (255, 255, 255)
# Background colour set to black
BGC = (0, 0, 0)
# Fixation mark time (milliseconds)
FIXTIME = 2000
# Image time (milliseconds)
IMGTIME = 10000
# Get the path to the current folder
DIR = os.path.dirname(os.path.abspath(__file__))
# Get the path to the image folder
IMGDIR = os.path.join(DIR, 'images')
# Get a list of all image names
IMGNAMES = os.listdir(IMGDIR)
# Sort IMGNAMES in alphabetical order
IMGNAMES.sort()

experiment.py:

import os
from constants import *
from pygaze.display import Display
from pygaze.screen import Screen
from pygaze.keyboard import Keyboard
from pygaze.eyetracker import EyeTracker
import pygaze.libtime as timer
# Initialise a Display to interact with the monitor
disp = Display()
# Initialise a Keyboard to collect key presses
kb = Keyboard(keylist=None, timeout=None)
# Create a Screen for the image task instructions
inscr = Screen()
inscr.draw_text(text='Please look at the images. \n\n(Press any key to begin)', fontsize=24)
# Create a Screen with a central fixation cross
fixscr = Screen()
fixscr.draw_fixation(fixtype='cross', diameter=8)
# Create a Screen to draw images on later
imgscr = Screen()
# Initialise a new EyeTracker
tracker = EyeTracker(disp)
# Calibrate the eye tracker
tracker.calibrate()
# Feed the instructions to the Display
disp.fill(inscr)
# Show the instructions
disp.show()
# Wait until the participant presses any key
# (Allowing them to read the instructions at their own pace)
kb.get_key()
# Loop through all image names
for imgname in IMGNAMES:
    # Construct the path to the image
    imgpath = os.path.join(IMGDIR, imgname)
    # Draw the image on imgscr
    # (clear imgscr first, to be sure it’s clean)
    imgscr.clear()
    imgscr.draw_image(imgpath)
    # Start recording gaze data
    tracker.start_recording()
    # Display a status message on the EyeLink computer
    # (EyeLink only; doesn’t do anything for other brands)
    tracker.status_msg(‘Trial with %s image’ % (imgname))
    # Log trial start
    tracker.log('TRIALSTART')
    # Feed the fixation Screen to the Display
    disp.fill(fixscr)
    # Update the monitor to show the fixation mark
    disp.show()
    # Log the fixation onset to the gaze data file
    tracker.log('fixation_onset')
    # Wait for the right duration
    timer.pause(FIXTIME)
    # Feed the image Screen to the Display
    disp.fill(imgscr)
    # Update the monitor to show the image
    disp.show()
    # Log the image onset to the gaze data file
    # Include the image name in the message!
    tracker.log('image_onset, imgname=%s' % (imgname))
    # Wait for the right duration
    timer.pause(IMGTIME)
    # Clear the Display
    disp.fill()
    # Update the monitor to show a blank screen
    disp.show()
    # Log the image offset
    tracker.log('image_offset')
    # Log the end of the trial
    tracker.log('TRIALEND')
    # Pause recording
    tracker.stop_recording()
# Clear the instructions Screen
inscr.clear()
# Write a new message
inscr.draw_text(text='All done!', fontsize=24)
# Feed the new message to the Display
disp.fill(inscr)
# Show the message
disp.show()
# Wait until the participant presses any key
# (Allowing them to read at their own pace)
kb.get_key()
# Close the connection to the eye tracker
# (This will also close the log file!)
tracker.close()
# Close the Display
disp.close()