input: Write a function to generate a set of unique random numbers in the range 0-10 using Python. If the range is less than or equal to 0, return an empty set.
  
  assert generate_unique_random_numbers(10)=={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  assert generate_unique_random_numbers(5)=={0, 1, 2, 3, 4, 5}
  assert generate_unique_random_numbers(-1)==set()
  assert generate_unique_random_numbers(0)==set()
output: import random
  
  def generate_unique_random_numbers(n):
      if n <= 0:
          return set()
      return set(random.sample(range(n + 1), n + 1))