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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 default_signal_map():
 """ Create the default signal map for this system. :return: dict """

    name_map = {
        'SIGTSTP': None,
        'SIGTTIN': None,
        'SIGTTOU': None,
        'SIGTERM': 'terminate'}
    signal_map = {}
    for name, target in list(name_map.items()):
        if hasattr(signal, name):
            signal_map[getattr(signal, name)] = target
    return signal_map