input: Write a function to find the Pythagorean triplet where the sum of a, b, and c equals 25.
  assert find_pythagorean_triplet(25) == (7, 24, 25)
  assert find_pythagorean_triplet(26) == (10, 24, 26)
  assert find_pythagorean_triplet(12) == (3, 4, 5)
output: def find_pythagorean_triplet(sum_total):
      for a in range(1, sum_total // 2):
          for b in range(a, sum_total // 2):
              c = sum_total - a - b
              if a * a + b * b == c * c:
                  return (a, b, c)
      return None