input: Write a function to generate a unique 6 digit number.
  
  ### Input:
  
  
  ### Output:
  # Python program to generate 
  # a unique 6 digit number 
  import random 
  def generate_number(): 
        
      # Choose a random number 
      # between 10000 and 99999 
      random_number = random.randint(10000, 99999) 
    
      # Return the random number 
      return random_number 
    
  # Driver Code 
  if __name__ == "__main__": 
      print(generate_number())
  
  assert generate_number() >= 10000
  assert generate_number() <= 99999
  assert generate_number() != generate_number()
  assert generate_number() != generate_number()
output: import random
  
  def generate_number():
      return random.randint(10000, 99999)