function bind(func, thisArg) {
    var methodName,
        isFunc = isFunction(func);

    // juggle arguments
    if (!isFunc) {
      methodName = thisArg;
      thisArg = func;
    }
    // use `Function#bind` if it exists and is fast
    // (in V8 `Function#bind` is slower except when partially applied)
    else if (isBindFast || (nativeBind && arguments.length > 2)) {
      return nativeBind.call.apply(nativeBind, arguments);
    }

    var partialArgs = slice.call(arguments, 2);

    function bound() {
      // `Function#bind` spec
      // http://es5.github.com/#x15.3.4.5
      var args = arguments,
          thisBinding = thisArg;

      if (!isFunc) {
        func = thisArg[methodName];
      }
      if (partialArgs.length) {
        args = args.length
          ? partialArgs.concat(slice.call(args))
          : partialArgs;
      }
      if (this instanceof bound) {
        // get `func` instance if `bound` is invoked in a `new` expression
        noop.prototype = func.prototype;
        thisBinding = new noop;

        // mimic the constructor's `return` behavior
        // http://es5.github.com/#x13.2.2
        var result = func.apply(thisBinding, args);
        return result && objectTypes[typeof result]
          ? result
          : thisBinding
      }
      return func.apply(thisBinding, args);
    }
    return bound;
  }
Creates a new function that, when called, invokes `func` with the `this`
binding of `thisArg` and prepends any additional `bind` arguments to those
passed to the bound function. Lazy defined methods may be bound by passing
the object they are bound to as `func` and the method name as `thisArg`.

@static
@memberOf _
@category Functions
@param {Function|Object} func The function to bind or the object the method belongs to.
@param {Mixed} [thisArg] The `this` binding of `func` or the method name.
@param {Mixed} [arg1, arg2, ...] Arguments to be partially applied.
@returns {Function} Returns the new bound function.
@example

// basic bind
var func = function(greeting) {
  return greeting + ' ' + this.name;
};

func = _.bind(func, { 'name': 'moe' }, 'hi');
func();
// => 'hi moe'

// lazy bind
var object = {
  'name': 'moe',
  'greet': function(greeting) {
    return greeting + ' ' + this.name;
  }
};

var func = _.bind(object, 'greet', 'hi');
func();
// => 'hi moe'

object.greet = function(greeting) {
  return greeting + ', ' + this.name + '!';
};

func();
// => 'hi, moe!'