If the file contains GOOD before execution, what will be content

Q. Read the code given below and answer the question:-

fh = open("main.txt", "W")
fh.write("Bye")
fh.close()

If the file contains “GOOD” before execution, what will be the contents of the file after execution of this code?

Answer :-

The file would now contain "Bye" only, because when an existing file is opened in write mode ("w"), it truncates the existing data the file.