input: Write a python function to generate a list of unique random numbers within a given range.
  assert isinstance(random_list(1, 10, 5), list)
  assert len(random_list(1, 10, 5)) == 5
  assert all(1 <= num < 10 for num in random_list(1, 10, 5))
  assert len(set(random_list(1, 5, 4))) == 4
output: import random
  
  def random_list(start, end, count):
      return random.sample(range(start, end), count)