text: exports._check = (x,y) => {
    // DRY up the codebase with this function
    // First, move the duplicate error checking code here
    // Then, invoke this function inside each of the others
    // HINT: you can invoke this function with exports._check()
  
    if (typeof x !== 'number') {
      throw new TypeError(`${x} is not a number`);
    }
    if (typeof y !== 'number') {
      throw new TypeError(`${y} is not a number`);
    }
  };
  
  exports.add = (x, y) => {
    exports._check(x,y)
    return x + y;
  };
  
  exports.subtract = (x, y) => {
    exports._check(x,y)
    return x - y;
  };
  
  exports.multiply = (x, y) => {
    exports._check(x,y)
    return x * y;
  };
  
  exports.divide = (x, y) => {
    exports._check(x,y)
    return x / y;
  };
  
  module.exports = exports;
  