src/CharCase.php
protected function changeCase($string)
    {
        if ($this->isLowercase()) {
            return strtolower($string);
        }

        if ($this->isUppercase()) {
            return strtoupper($string);
        }

        return $string;
    }
protected function changeCase($string)
    {
        if ($this->isLowercase()) {
            return strtolower($string);
        }

        if ($this->isUppercase()) {
            return strtoupper($string);
        }

        return $string;
    }
protected function changeCase ( $ string ) { if ( $ this -> isLowercase ( ) ) { return strtolower ( $ string ) ; } if ( $ this -> isUppercase ( ) ) { return strtoupper ( $ string ) ; } return $ string ; }
Return a string in the proper case.

@param $string
@return string
Return a string in the proper case .