st4.py

for i, page in enumerate(pages):
    if i == 0:
        with open('my_file.csv', 'w') as file:
            file.write(f'{col_1},{col_2},{col_3}')
            
    '''
    Here's your scraper
    '''
   
     with open('my_file.csv', 'a') as file:
         file.write(f'{value_1},{value_2},{value_3}')