old_contents: // Write a function that looks at both params and returns true
  // if either param is true or false, but returns false otherwise.
  
  function xor(a, b) {
    // Your code goes here.
  }
  
  module.exports = xor;
new_contents: // Write a function that looks at both params and returns true
  // if either param is true or false, but returns false otherwise.
  
  function xor(a, b) {
    return a ^ b;
  }
  
  module.exports = xor;
subject: fix the xor method