input: Write a python function to find the maximum value among three numbers.
  assert getMax(2, 5, 7) == 7
  assert getMax(10, 5, 7) == 10
  assert getMax(2, 50, 7) == 50
  assert getMax(1, 1, 1) == 1
output: def getMax(a, b, c):
      return max(a, b, c)