protected function getAllowedTypes(array $options)
    {
        $types = null;

        if (isset($options['file_types'])) {

            $types = $options['file_types'];
            $self  = $this;

            if (!is_array($types)) {
                $types = explode(',', $types);
                $types = array_map('trim', $types);
            }

            array_walk(
                $types,
                function (&$val) use ($self) {
                    if (false == preg_match('#^([^/]+)/([\w|\.|\-]+)#', $val)) {
                        $val = $self->getMimeType($val);
                    }
                }
            );
        }

        return $types;
    }