input: Write a python function to find two numbers in a list that add up to a given integer.
  assert find_pair([3, 5, 10, 15], 17) == (10, 7)
  assert find_pair([1, 2, 3, 4, 5], 9) == (4, 5)
  assert find_pair([2, 4, 6, 8], 12) == (4, 8)
output: def find_pair(numbers, target):
      seen = {}
      for number in numbers:
          complement = target - number
          if complement in seen:
              return (complement, number)
          seen[number] = True