input: 
  import random 
  
  def generate_number() -> int:
      """ Generate a unique 6-digit number.
      >>> generate_number()
      12345
      >>> generate_number()
      98765
      """
      # Choose a random number between 10000 and 99999 
      random_number = random.randint(10000, 99999) 
    
      # Return the random number 
      return random_number 
  
output:     return random_number