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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 print_email(message, app):
 """Print mail to stream. Signal handler for email_dispatched signal. Prints by default the output to the stream specified in the constructor of InvenioMail. :param message: Message object. :param app: Flask application object. """

    invenio_mail = app.extensions['invenio-mail']
    with invenio_mail._lock:
        invenio_mail.stream.write(
            '{0}\n{1}\n'.format(message.as_string(), '-' * 79))
        invenio_mail.stream.flush()