input: Write a function to check if any two numbers from the given list sum up to the target. If two such numbers are found, 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([3, 4], 7)==True
  assert check_sum([3, 5, 7, 8], 11)==True
  assert check_sum([1, 2, 3, 4, 5], 9)==True
  assert check_sum([9, 7, 5, 3], 4)==False
  assert check_sum([], 99)==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