What parameter should use in preprocessing

[bab]

I have an item that it returns follow output :

[{"TABLESPACE_NAME":"TBSSPOT","FREE_SPACE_GB":"4"},{"TABLESPACE_NAME":"SYSAUX","FREE_SPACE_GB":"15"},{"TABLESPACE_NAME":"SYSTEM","FREE_SPACE_GB":"29"},{"TABLESPACE_NAME":"TBS_USER_AUDIT","FREE_SPACE_GB":"30"},{"TABLESPACE_NAME":"BANK_TRANS","FREE_SPACE_GB":"32"},{"TABLESPACE_NAME":"ILINK_DAT","FREE_SPACE_GB":"32"},{"TABLESPACE_NAME":"DM_TRANS","FREE_SPACE_GB":"32"},{"TABLESPACE_NAME":"ILINK_IDX","FREE_SPACE_GB":"32"},{"TABLESPACE_NAME":"TBS_AUX","FREE_SPACE_GB":"56"},{"TABLESPACE_NAME":"UNDOTBS2","FREE_SPACE_GB":"67"},{"TABLESPACE_NAME":"DAILY_TRANS","FREE_SPACE_GB":"106"},{"TABLESPACE_NAME":"BGTBS","FREE_SPACE_GB":"106"},{"TABLESPACE_NAME":"USERS","FREE_SPACE_GB":"375"},{"TABLESPACE_NAME":"TESTRETAIL_TBS","FREE_SPACE_GB":"448"}]

I know we can define it such as follow output by preprocessing but don't know what paramters should fill in ?

TBSSPOT = 4G

SYSAUX = 15G