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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 legitimize(text):
 """Converts a string to a valid filename. """

    import platform
    os_ = platform.system()
    # POSIX systems
    text = text.translate({
        0: None,
        ord('/'): '-',
        ord('|'): '-',
    })

    if os_ == 'Windows':
        # Windows (non-POSIX namespace)
        text = text.translate({
            # Reserved in Windows VFAT and NTFS
            ord(':'): '-',
            ord('*'): '-',
            ord('?'): '-',
            ord('\\'): '-',
            ord('\"'): '\'',
            # Reserved in Windows VFAT
            ord('+'): '-',
            ord('<'): '-',
            ord('>'): '-',
            ord('['): '(',
            ord(']'): ')',
        })
    else:
        # *nix
        if os_ == 'Darwin':
            # Mac OS HFS+
            text = text.translate({
                ord(':'): '-',
            })

        # Remove leading .
        if text.startswith("."):
            text = text[1:]

    text = text[:82]  # Trim to 82 Unicode characters long
    return text