def checkin(pickledata):
    config = pickle.loads(bz2.decompress(base64.urlsafe_b64decode(pickledata)))
    r, message = read_host_config(SESSION, config)
    if r is not None:
        return message + 'checked in successful'
    else:
        return message + 'error checking in'
The software constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.