input: Write a python function to generate n random numbers within a given range.
  assert len(random_numbers(-10, 10, 20)) == 20
  assert all(-10 <= num <= 10 for num in random_numbers(-10, 10, 20))
  assert len(set(random_numbers(-10, 10, 20))) <= 20
output: import random
  
  def random_numbers(start, end, n):
      return [random.randint(start, end) for _ in range(n)]