Type error: dump() missing 1 required positional argument: fp

[snippsat]

To make it work,also for now remove stuff that don't make sense.

import json

def ussubem():
    sub_e = input('Please enter your subscription email: \n ')
    return f'Thank you, will now receive regular emails about The Urban Macchiato to {sub_e}'

email = ussubem()
with open('usersub.json', 'w') as json_file:
    json.dump(email, json_file)

When you do userfav = True it's overwrite function userfav() then all code is gone and it's only True.
To check a condition in function then something like this:

if 'email stuff' in userfav():
    # Write json
else:
    # Not okay,try again