how to keep the code running after log in (python 3)

i am trying to write a programe that lets the user create a log in and then it runs a menu system. the problem i have is it keeps looping the log in code instead of moving onto the next part which is the menu bit. i have tried adding break commands but this seemed to stop after the log in but not run the next part.

# Aaron Dyer Software Engineering Fundamentals Data Base## #
# A Prompt asking the user to log in#
print("Please enter log in details")
# The below code will allow the user to create a username and password and log in"
def add_new_user():
username = input("Enter your username: ")
password = input("Enter your password: ")
user_type = input("Enter your user type (admin, inventory-checker): ")
with open("userdata.txt", "a") as f:
f.write("%s %s %s\n" % (username, password, user_type))
def user_authentication():
username = input("Enter your username: ")
password = input("Enter your password: ")
with open("userdata.txt", "r") as f:
for line in f:
user_data = line.split()
if user_data[0] == username and user_data[1] == password:
print("Login successful!")
return user_data[2]
print("Incorrect password or username.")
return None
def main():
add_new_user()
while True:
user_type = user_authentication()
if user_type is None:
continue
if user_type == "admin":
print("You are logged in as an admin.")
continue
elif user_type == "inventory-checker":
continue
print("You are logged in as an inventory checker.")
if __name__ == "__main__":
main()
#Below is the menu stystem to access the detials about the laptops and iphone's#
def menu():
print("[1] Laptops")
print("[2] iPhones")
option = input("Choose your device: ")
if option == "1":
print("[1] S5750")
print("[2] S5577")
print("[3] S5563")
print("[4] S5744")
print("[5] S5765")
print("[6] S5944")
print("[7] S5507")
print("[8] S5509")
laptop_option = input("Choose your laptop: ")
# do something based on the chosen laptop
elif option == "2":
# add options for iPhones here
pass
else:
print("Invalid choice. Please try again.")

You just need to put the menu function before main .
and just go to menu function after check that is admin or inventory checker .

worked program

that is your code after editing :

# Aaron Dyer Software Engineering Fundamentals Data Base## #
# A Prompt asking the user to log in#
print("Please enter log in details")
# The below code will allow the user to create a username and password and log in"
def add_new_user():
username = input("Enter your username: ")
password = input("Enter your password: ")
user_type = input("Enter your user type (admin, inventory-checker): ")
with open("userdata.txt", "a") as f:
f.write("%s %s %s\n" % (username, password, user_type))
def user_authentication():
username = input("Enter your username: ")
password = input("Enter your password: ")
with open("userdata.txt", "r") as f:
for line in f:
user_data = line.split()
if user_data[0] == username and user_data[1] == password:
print("Login successful!")
return user_data[2]
print("Incorrect password or username.")
return None
def menu():
print("[1] Laptops")
print("[2] iPhones")
option = input("Choose your device: ")
if option == "1":
print("[1] S5750")
print("[2] S5577")
print("[3] S5563")
print("[4] S5744")
print("[5] S5765")
print("[6] S5944")
print("[7] S5507")
print("[8] S5509")
laptop_option = input("Choose your laptop: ")
# do something based on the chosen laptop
elif option == "2":
# add options for iPhones here
pass
else:
print("Invalid choice. Please try again.")
def main():
add_new_user()
while True:
user_type = user_authentication()
if user_type is None:
continue
if user_type == "admin":
print("You are logged in as an admin.")
menu()
continue
elif user_type == "inventory-checker":
menu()
print("You are logged in as an inventory checker.")
if __name__ == "__main__":
main()
#Below is the menu stystem to access the detials about the laptops and iphone's#