def parse_type(text):
    """ "normalize" a mime type

    >>> parse_type('text/plain')
    'text/plain'

    >>> parse_type('text')
    'application/octet-stream'

    >>> parse_type('')
    'application/octet-stream'

    >>> parse_type(None)
    'application/octet-stream'
    """
    if not text or '/' not in text:
        return 'application/octet-stream'
    return text
