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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def init_tasks():
 """ Performs basic setup before any of the tasks are run. All tasks needs to run this before continuing. It only fires once. """


    # Make sure exist are set
    if "exists" not in env:
        env.exists = exists

    if "run" not in env:
        env.run = run

    if "cd" not in env:
        env.cd = cd

    if "max_releases" not in env:
        env.max_releases = 5

    if "public_path" in env:
        public_path = env.public_path.rstrip("/")
        env.public_path = public_path

    run_hook("init_tasks")