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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 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