As Celery documentation tells, assume there is a custom class called DatabaseTask.

from celery import Task

class DatabaseTask(Task):
    _db = None

    @property
    def db(self):
        if self._db is None:
            self._db = Database.connect()
        return self._db

This custom class can be passed in Celery app when instantiating the app.

app = Celery('tasks', DatabaseTask)

Now, how to use db property in tasks that are declared using the decorator syntax within your app. For example, How can I use db property in collect_data task?

@app.task
def collect_data():
    #
    #