import re
item = '"last_name,""first_name"",""middle_name"",""birthday"",""passport_series"",""passport_number"",""mfo_name"",""created_at"",""status"""'
regex = re.compile(r'(?<!"),""')
tmp = '""' + regex.sub('"",""', item.strip('"')) + '""'
print(tmp)
aW1wb3J0IHJlCgppdGVtID0gJyJsYXN0X25hbWUsIiJmaXJzdF9uYW1lIiIsIiJtaWRkbGVfbmFtZSIiLCIiYmlydGhkYXkiIiwiInBhc3Nwb3J0X3NlcmllcyIiLCIicGFzc3BvcnRfbnVtYmVyIiIsIiJtZm9fbmFtZSIiLCIiY3JlYXRlZF9hdCIiLCIic3RhdHVzIiIiJwpyZWdleCA9IHJlLmNvbXBpbGUocicoPzwhIiksIiInKQp0bXAgPSAnIiInICsgcmVnZXguc3ViKCciIiwiIicsIGl0ZW0uc3RyaXAoJyInKSkgKyAnIiInCnByaW50KHRtcCk=
""last_name"",""first_name"",""middle_name"",""birthday"",""passport_series"",""passport_number"",""mfo_name"",""created_at"",""status""