def guess_os(scope):
    """
    Guesses the operating system of the connected host.

    The recognition is based on the past conversation that has happened
    on the host; Exscript looks for known patterns and maps them to specific
    operating systems.

    :rtype:  string
    :return: The operating system.
    """
    conn = scope.get('__connection__')
    return [conn.guess_os()]