Why doesn't append work in Google Sheets?

Question

Python

I try once in a while to enter data into a table, but my code either works or doesn't work. The task is as follows: I want the data to be sequentially entered one after the other, but he either writes it down or does not write it down. Here is the code itself:

service.spreadsheets().values().append(
                    spreadsheetId=spreadsheet_id,
                    range="B294:B294",
                    body={
                        "values": 
                    },
                    valueInputOption="USER_ENTERED"
                ).execute()

Answer 1

The error does not occur in this part of the code.
If the debugger points to it, then it's probably not defining variables somewhere, for example, total_sum.