input: Write a python function to check if the sum of any two numbers equals the third number.
  assert check_triplet_sum(3, 1, 2) == True
  assert check_triplet_sum(10, 5, 5) == True
  assert check_triplet_sum(1, 2, 4) == False
output: def check_triplet_sum(a, b, c):
      return a + b == c or a + c == b or b + c == a