src/Transformers/TransformerResolver.php
public function bind($transformable, $transformer = null)
    {
        $this->bindings = array_merge($this->bindings, is_array($transformable) ? $transformable : [
            $transformable => $transformer,
        ]);
    }
public function bind($transformable, $transformer = null)
    {
        $this->bindings = array_merge($this->bindings, is_array($transformable) ? $transformable : [
            $transformable => $transformer,
        ]);
    }
Register a transformable to transformer binding.

@param  string|array         $transformable
@param  string|callback|null $transformer
@return void