input: Write a python function to find pairs of numbers in a list that add up to a given target.
  assert find_pairs_with_sum([1, 2, 3, 4, 5], 4) == [[3, 1]]
  assert find_pairs_with_sum([1, 1, 2, 2], 3) == [[2, 1], [2, 1]]
  assert find_pairs_with_sum([0, -1, 2, -3, 1], -2) == [[-3, 1]]
output: def find_pairs_with_sum(numbers, target):
      pairs = []
      seen = set()
      for number in numbers:
          complement = target - number
          if complement in seen:
              pairs.append([number, complement])
          seen.add(number)
      return pairs