input: Write a function to generate a random 6-digit number in Python.
  
  def generate_6_digit_number():
      import random
      return random.randint(100000, 999999)
  
  assert generate_6_digit_number() >= 100000
  assert generate_6_digit_number() <= 999999
output: def generate_6_digit_number():
      import random
      return random.randint(100000, 999999)