text: let mathEnforcer = {
      addFive: function (num) {
          if (typeof (num) !== 'number') {
              return undefined;
          }
          return num + 5;
      },
      subtractTen: function (num) {
          if (typeof (num) !== 'number') {
              return undefined;
          }
          return num - 10;
      },
      sum: function (num1, num2) {
          if (typeof (num1) !== 'number' || typeof (num2) !== 'number') {
              return undefined;
          }
          return num1 + num2;
      }
  };
  
  module.exports.mathEnforcer = mathEnforcer;