result="$(sed -e "1,${line_num}d;" <<< "$tree" \
| sed -e "/^$TAB\{1,$level\}$_gsu_node_name_pattern/,\$d" \
| sed -e "/^$TAB\{$(($level + 2))\}/d")"
result="$(sed -e "1,${line_num}d;" <<< "$tree" \
| sed -e "/^$TAB\{1,$level\}$_gsu_node_name_pattern/,\$d" \
| sed -e "/^$TAB\{$(($level + 2))\}/d")"