_.memoize = function(func) {
    var alreadyCalled = false;
    var result;
    var arr = [];
    return function() {
      //console.log(arguments[0]);
      if (!alreadyCalled) {
        if ( !(arr.join(' ')).includes(arguments[0])) {
          arr.push(arguments[0]);
          result = func.apply(this, arguments);
          alreadyCalled = true;
        } else {
          //arr.push(arguments[0]);
          alreadyCalled = true;
        }
        return result;
      }
      return result;
    };

  };