input: Write a function to generate an even number between 10 and 200 that is divisible by 5. If such a number is generated, return it. If no such number can be generated within the range, return None.
  assert generate_even_number()==80
  assert generate_even_number()==100
  assert generate_even_number()==130
  assert generate_even_number()==170
  assert generate_even_number()==200
output: import random
  
  def generate_even_number():
      for _ in range(100):
          num = random.randint(10, 200)
          if num % 2 == 0 and num % 5 == 0:
              return num
      return None