def _get_header(request_type):
    """Returns header str for talking with cosmos

    :param request_type: name of specified request (ie uninstall-request)
    :type request_type: str
    :returns: header information
    :rtype: str
    """

    return ("application/vnd.dcos.package.{}+json;"
            "charset=utf-8;version=v1").format(request_type)