Call function in if statement - Python3 [duplicate]

Question

So I'm trying to code a login dialogue in the terminal with Python3 but for some reason this code:

def start():

    login_signin_Confirmation = input("Welcome! Do you wish to log-in to your account or sign up to this platform? \n")

    if login_signin_Confirmation == "login":
        
        login()
    else:
        signup()       
start()

def login():

    login_username = input("Great! start by typing in your username.")

    if login_username in users:
        print("Welcome Back, {login_username}")
login()

prompts me this error message:

Welcome! Do you wish to log-in to your account or sign up to this platform? 
login
Traceback (most recent call last):
  File "login.py", line 22, in <module>
    start()
  File "login.py", line 19, in start
    login()
NameError: name 'login' is not defined

Just started out some I'm not really sure what I did wrong and I couldn't find somebody with the same problem...

Answer 1

as others pointed out, You need first to define, then to call a function :

# imports first

# now definitions of functions

def start():
    login_signin_Confirmation = input("Welcome! Do you wish to log-in to your account or sign up to this platform? \n")
    if login_signin_Confirmation == "login":
        login()
    else:
        signup()       

def signup():
    pass

def login():
    login_username = input("Great! start by typing in your username.")
    if login_username in users:
        print("Welcome Back, {login_username}")


# main 
def main():
    start()

# guard multiprocess context
if __name__ == '__main__':
    main()