input: Write a python function to generate a list of unique random integers between 1 and n.
  assert len(generate_unique_list(10)) == 10
  assert len(generate_unique_list(5)) == 5
  assert len(set(generate_unique_list(20))) == 20
output: import random
  
  def generate_unique_list(n):
      return random.sample(range(1, n+1), n)