How to handle column separator being present in one of the columns without using any in-built library in Python?

I want to read a CSV file in Python3 but cannot use any library due to some constraints. In almost every row, one or more columns contain the commas (“,”) and using row.split(‘,’) is causing issues as the number of columns to get increased. My code is: import csv file_name = “train_1.csv” columns = [ […]