input: Write a python function to check if two values are equal and add one to a third value if they are.
  assert check_and_add(5, 5, 3) == 4
  assert check_and_add(10, 20, 5) == 5
  assert check_and_add('a', 'a', 0) == 1
output: def check_and_add(value1, value2, value3):
      if value1 == value2:
          return value3 + 1
      return value3