If os.path.exists(file) Check

You can achieve this using the os module in Python which provides functions for interacting with the operating system. The os.path.exists() function is used to check if a file or directory exists.

Here is the code:

import os

if os.path.exists('latest.md'):
    append_to_file()
else:
    write_to_file()

This code checks if a file named 'latest.md' exists in the same directory as your script. If it does exist, it calls the append_to_file() function. If it does not exist, it calls the write_to_file() function.

Note: This assumes that append_to_file() and write_to_file() are defined somewhere in your code.

For example:

def append_to_file():
    with open('latest.md', 'a') as file:
        file.write('Appending some data')

def write_to_file():
    with open('latest.md', 'w') as file:
        file.write('Writing some data')

In the append_to_file() function, the 'a' parameter in the open() function opens the file in append mode, and in the write_to_file() function, the 'w' parameter opens the file in write mode.