Input and output file prompts in python

file_prompts.py

import os.path

def input_file_prompt():
    """ () -> string

    Precondition: none

    This function returns back a filename that the user wants to read data from. It also checks to see
    if the file already exists and if not, informs the users and prompts them to try again.

    """
    fileName = input('Enter the name of the file to read from: ')
    while not os.path.isfile(fileName):
        print('The specified file can not be found. Please try again.')
        fileName = input('Enter the name of the file to read from: ')
    return fileName
        


def output_file_prompt():
    """ () -> string

    Precondition: none

    This function returns back a filename that the user wants to write data to. It also checks to see
    if the file already exists and confirms with the user if they want to overwrite it. The function
    returns back an empty string if the user has canceled out of the operation.

    """
    fileName = input('Enter the name of the file to write to: ')
    while os.path.isfile(fileName):
        overwrite = input('The file exists. Do you want to choose another file name ("choose"), overwrite the file ("overwite"), or cancel ("cancel")? ')
        overwrite = overwrite.strip().lower()
        if overwrite == 'choose':
            #prompt again
            #do name check again
            return output_file_prompt()
        elif overwrite == 'overwrite':
            #user wants to use same file name so return that
            return fileName
        elif overwrite == 'cancel':
            return ''
        else:
            continue
    return fileName