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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 faz(input_file, variables=None):
 """ FAZ entry point. """

    logging.debug("input file:\n {0}\n".format(input_file))
    tasks = parse_input_file(input_file, variables=variables)
    print("Found {0} tasks.".format(len(tasks)))
    graph = DependencyGraph(tasks)
    graph.show_tasks()
    graph.execute()