How to replace text in file with Python

replaceTextInFile.py

#!/usr/bin/env python
import os
import subprocess

PWD = os.getcwd()
file_name = 'data.txt'
file_path = os.path.join(PWD, file_name)

def replaceTextInFile(file_path, oldText, newText):
    # Read in the file
    with open(file_path) as file:
        file_data = file.read()

    # Replace the target string
        file_data = file_data.replace(oldText, newText)

    # Write the file out again
    with open(file_path, 'w') as file:
        file.write(file_data)

replaceTextInFile(file_path, 'Khoai To', '')
os.system('cat data.txt')