input: Write a function to generate a list of random numbers within a specified range and of a specified length. If the specified length is zero or negative, return an empty list.
  assert generate_random_numbers(5, 1, 10)
  assert generate_random_numbers(3, -5, 5)
  assert generate_random_numbers(0, 1, 10)==[]
  assert generate_random_numbers(-1, 1, 10)==[]
output: import random
  
  def generate_random_numbers(length, start, end):
      if length <= 0:
          return []
      return [random.randint(start, end) for _ in range(length)]