when I try to run my program it won't run : I'm very very new to python and I'm I've got this exercise and like the first part of the program was running fine and I must've done something because now when I try to run it will just show => None and and nothing seems to be 'wrong'. and I don't know enough to even figure out what's wrong. 


def main():
	"""Gets the job done"""
	
	#this program returns the value according to the colour
	def re_start():
		#do the work
		return read_colour
		
	def read_names():
		"""prompt user for their name and returns in a space-separaded line"""
		PROMPT_NAMES = input("Enter names: ")
		users_names = '{}'.format(PROMPT_NAMES)
		print (users_names)
		return users_names
		
	def read_colour():
		"""prompt user for a colour letter if invalid colour enter retry"""
		ALLOWED_COLOURS = ["whero",
                   "kowhai",
                   "kikorangi",
                   "parauri",
                   "kiwikiwi",
                   "karaka",
                   "waiporoporo",
                   "pango"]
		PROMPT_COLOUR = input("Enter letter colour: ").casefold()
		
		if PROMPT_COLOUR in ALLOWED_COLOURS:
			return read_names()
			
		else:
			print("Invalid colour...")
			print(*ALLOWED_COLOURS,sep='\n')
			re_start()
main() 