Stalker's Calculator - Menu and Options

print('Stalker's Calculator\n\nMenu:\n(a) Estimate Astral Projection Mana Burn\n(b) [LOCKED] Estimate Astral Slingshot Approach Vector\n(c) Enter License Key\n(d) Exit Stalker's Calculator') choice = input('What would you like to do, ' + username_trial + ' (a/b/c/d)? ')

if not validate_choice(choice): print('\n\nInvalid choice!\n\n') return None

if choice == 'a': estimate_burn() elif choice == 'b': locked_estimate_vector() elif choice == 'c': enter_license() elif choice == 'd': sta1k3r_loop_trial = False print('Bye!') else: print('That choice is not valid. Please enter a single, valid lowercase letter choice (a/b/c/d).')

return None