input: Write a function to generate a random 6-digit number in Python. The function should return the generated number as an integer.
  assert generate_6_digit_number()>100000
  assert generate_6_digit_number()<1000000
  assert isinstance(generate_6_digit_number(), int)
  assert len(str(generate_6_digit_number()))==6
  assert generate_6_digit_number()>100000
  assert generate_6_digit_number()<1000000
  assert isinstance(generate_6_digit_number(), int)
  assert len(str(generate_6_digit_number()))==6
output: import random
  
  def generate_6_digit_number():
      return random.randint(100000, 999999)