Подгрузка списков в Python

#!/usr/bin/env python
 
contr = []
list1 = []
list2 = []
with open('base.txt', 'r') as a, open('file1.txt', 'r') as b, open('file2.txt', 'r') as c:
    contr = a.read().split()
    list1 = b.read().split()
    list2 = c.read().split()
    sb = set(list1)
    sc = set(list2)
for word in contr: 
    if word in sb or word in sc:
        print([f'{word}'])

import os
filenames = os.listdir(os.getcwd)

from contextlib import contextmanager
 
@contextmanager
def multi_file_manager(files, mode='rt'):
    """ Open multiple files and make sure they all get closed. """
    files = [open(file, mode) for file in files]
    yield files
    for file in files:
        file.close()
 
filenames = 'file1', 'file2', 'file3'
 
with multi_file_manager(filenames) as files:
    a = files[0].readline()
    b = files[2].readline()
        ...

MyList = ["Самара", "Сочи", "Мурманск", "Анапа"] 
MyFile=open('output.txt', 'w', encoding='utf-8')
for element in MyList:
     MyFile.write(element)
     MyFile.write('\n')
MyFile.close()

def sum_ints_in_file(file_name):
    with open(file_name, 'r') as fp:
        return sum(map(int, fp.read().split()))#читаем то, что в файле с ходу)
 
 
print(sum_ints_in_file('file.txt'))
if __name__ == '__main__':
    filename = input()
    sum_ints_in_file(file_name='1.txt')

files = ['file.txt', 'file1.txt', 'file2.txt']
for file in files:
    with open(file) as f:
        text = f.read() #  если хочешь прочитать сразу весь файл
        #for line in f:  # если хочешь читать построчно
        #   print(line)