public function data()
{
$args = func_get_args();
if (isset($args[0]) and is_array($args[0])) {
$this->data = array_merge($this->data, array_change_key_case($args[0]));
return $this;
} elseif (isset($args[0]) and isset($args[1])) {
$this->data[strtolower($args[0])] = $args[1];
return $this;
} elseif (isset($args[0])) {
return isset($this->data[$args[0]]) ? $this->data[$args[0]] : null;
}
return $this->data;
}