input: Write a function to generate a unique 6 digit number.
  def generate_number():
      random_number = random.randint(10000, 99999)
      return random_number
  assert generate_number()==56789
  assert generate_number()==12345
  assert generate_number()==98765
  assert generate_number()==45678
  assert generate_number()==23456
output: import random
  
  def generate_number():
      random_number = random.randint(10000, 99999)
      return random_number