input: Write a function to check if any two numbers from a given list of numbers sum up to a given target number. If they do, return True; otherwise, return False.
  def check_sum(numbers, target):
      for i in range(len(numbers)):
          for j in range(i+1, len(numbers)):
              if numbers[i] + numbers[j] == target:
                  return True
      return False
  
  assert check_sum([1, 2, 3, 4, 5], 9)==True
  assert check_sum([1, 2, 3, 4, 5], 10)==False
  assert check_sum([-1, 0, 3, 4, 5], 2)==True
  assert check_sum([-1, 0, 3, 4, 5], 1)==True
  assert check_sum([], 3)==False
output: def check_sum(numbers, target):
      for i in range(len(numbers)):
          for j in range(i+1, len(numbers)):
              if numbers[i] + numbers[j] == target:
                  return True
      return False