input: Write a python function to create a simple calculator that takes two numbers and an operation as arguments and returns the result.
  assert simple_calculator(10, 5, '+') == 15
  assert simple_calculator(10, 5, '-') == 5
  assert simple_calculator(10, 5, '*') == 50
  assert simple_calculator(10, 5, '/') == 2
  assert simple_calculator(10, 0, '/') == "Invalid operation"
output: def simple_calculator(num1, num2, operation):
      if operation == '+':
          return num1 + num2
      elif operation == '-':
          return num1 - num2
      elif operation == '*':
          return num1 * num2
      elif operation == '/':
          if num2 == 0:
              return "Invalid operation"
          return num1 / num2
      else:
          return "Invalid operation"