private function setUserInfo($username, $password = null)
	{
		$this->username = $username;
		$this->password = $password;

		return $this;
	}
private function setUserInfo($username, $password = null)
	{
		$this->username = $username;
		$this->password = $password;

		return $this;
	}
private function setUserInfo ( $ username , $ password = null ) { $ this -> username = $ username ; $ this -> password = $ password ; return $ this ; }
Set the user info.

@param string $username
@param string|null $password = null
@return $this
Set the user info .