input: 
  def generate_unique_number() -> int:
      """ Generate a unique 6-digit number.
      >>> generate_unique_number()
      12345
      >>> generate_unique_number()
      67890
      """
      import random 
      return random.randint(100000, 999999)
  
  # Driver Code
  if __name__ == "__main__": 
      print(generate_unique_number())
  
output:     import random 
      return random.randint(100000, 999999)