def is_valid_mimetype(response):
    """ Return ``True`` if the mimetype is not blacklisted.

    :rtype: bool

    """
    blacklist = [
        'image/',
    ]

    mimetype = response.get('mimeType')
    if not mimetype:
        return True

    for bw in blacklist:
        if bw in mimetype:
            return False

    return True
Return ``True`` if the mimetype is not blacklisted.

    :rtype: bool