[Python] I am unsure where the error keeps popping up

I am trying to automate updating of a google sheet using lists. Below is the latest iteration of my code

import gspread
import pandas as pd
gc = gspread.service_account(filename="credentials.json")
sh = gc.open('GCE MCQ')
wks=['2024','2023','2022','2021','2020','2019','2018','2017','2016','2015','2014','2013','2012','2011','2010']
lsts=list()
t=open('list3.txt')
for line in t:
lists=lsts.append(line)
x=0

for wk in wks:
worksheet = sh.worksheet(wk)
body = [{


"requests": [

{"findReplace": {
"find": str(x+1),
"searchByRegex": True,
"range": {
"sheetId": worksheet.id,
"startColumnIndex": 4,
"endColumnIndex":5
},
"replacement":lsts[x]},}

]}

]
while x<58:
sh.batch_update(body)
x=x+1


It is unclear where the error keeps popping up from as using the above code without any lists, for/in and while works perfectly.

Traceback (most recent call last):
File "C:\Users\USER\p4ey\attempt2.py", line 33, in <module>
sh.batch_update(body)
~~~~~~~~~~~~~~~^^^^^^
File "C:\Users\USER\AppData\Local\Programs\Python\Python313\Lib\site-packages\gspread\spreadsheet.py", line 101, in batch_update
return self.client.batch_update(self.id, body)
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
File "C:\Users\USER\AppData\Local\Programs\Python\Python313\Lib\site-packages\gspread\http_client.py", line 139, in batch_update
r = self.request("post", SPREADSHEET_BATCH_UPDATE_URL % id, json=body)
File "C:\Users\USER\AppData\Local\Programs\Python\Python313\Lib\site-packages\gspread\http_client.py", line 128, in request
raise APIError(response)
gspread.exceptions.APIError: APIError: [400]: Invalid JSON payload received. Unknown name "": Root element must be a message.

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