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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 requestCheckDockerIo(origAppliance, imageName, tag):
 """ Checks docker.io to see if an image exists using the requests library. URL is based on the docker v2 schema. Requires that an access token be fetched first. :param str origAppliance: The full url of the docker image originally specified by the user (or the default). e.g. "ubuntu:latest" :param str imageName: The image, including path and excluding the tag. e.g. "ubuntu" :param str tag: The tag used at that docker image's registry. e.g. "latest" :return: Return True if match found. Raise otherwise. """

    # only official images like 'busybox' or 'ubuntu'
    if '/' not in imageName:
        imageName = 'library/' + imageName

    token_url = 'https://auth.docker.io/token?service=registry.docker.io&scope=repository:{repo}:pull'.format(repo=imageName)
    requests_url = 'https://registry-1.docker.io/v2/{repo}/manifests/{tag}'.format(repo=imageName, tag=tag)

    token = requests.get(token_url)
    jsonToken = token.json()
    bearer = jsonToken["token"]
    response = requests.head(requests_url, headers={'Authorization': 'Bearer {}'.format(bearer)})
    if not response.ok:
        raise ApplianceImageNotFound(origAppliance, requests_url, response.status_code)
    else:
        return origAppliance