Nice tutorial!

Noticed 3 errors though:

1. You will also have to enable Google Sheet API for the project to work, otherwise, you will get an exception when you start the worker.py.
2. You are missing this function here in the tutorial, which formats the cells from the Google spreadsheet:

def __num_suffix(self, check_in_date):
    """
    Strip the date suffix and return the date
    Before comparing the date
    """
    date_value = str(check_in_date).split(' ')
    day_value = date_value[0][:-2]
    date_value[0] = day_value
    return ' '.join(date_value)

3. in notify_channel(…) you call the function with 1underscore only, it’s name is __num_suffix and not _num_suffix.

Best