src/Metable/Attribute.php
protected function hasMutator($value, $dir = 'setter', $type = null)
    {
        return (bool) $this->getMutator($value, $dir, $type);
    }
protected function hasMutator($value, $dir = 'setter', $type = null)
    {
        return (bool) $this->getMutator($value, $dir, $type);
    }
Determine whether a mutator exists for the value type.

@param  mixed   $value
@param  string  $dir
@return boolean