Mine

fetch() {
    USER=$1
    HOST=$2
    REMOTE_DIR=$3
    REMOTE_FILE=$4
    LOCAL_TYPE_NAME=$5
    LOCAL_RENAME_SCRIPT=$6
    for i in USER HOST REMOTE_DIR REMOTE_FILE LOCAL_TYPE_NAME LOCAL_RENAME_SCRIPT; do
        if [ -z "${!i}" ]; then
            errmsg "Parameter $i is empty but required"
            return
        fi
    done
}