Python - Fileinput

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from fileinput import FileInput
from re import findall


def replacement(file, regex, newphrase):
    try:
        with FileInput(file, inplace=True, backup='.bak') as file_founded:
            for line in file_founded:
                if findall(regex, line):
                    print(newphrase, end='\n')
                else:
                    print(line, end='')
    except FileNotFoundError as err:
        print(err)


if __name__ == '__main__':
    replacement('testadeiro.txt', '^homem', 'mulher')