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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 post_message(consumers, lti_key, url, body):
 """ Posts a signed message to LTI consumer :param consumers: consumers from config :param lti_key: key to find appropriate consumer :param url: post url :param body: xml body :return: success """

    content_type = 'application/xml'
    method = 'POST'
    (_, content) = _post_patched_request(
        consumers,
        lti_key,
        body,
        url,
        method,
        content_type,
    )

    is_success = b"<imsx_codeMajor>success</imsx_codeMajor>" in content
    log.debug("is success %s", is_success)
    return is_success