concrete/src/Csv/EscapeFormula.php
protected function filterSpecialCharacters(array $characters)
    {
        foreach ($characters as $str) {
            if (1 != strlen($str)) {
                throw new InvalidArgumentException(sprintf('The submitted string %s must be a single character', $str));
            }
        }
        return $characters;
    }
protected function filterSpecialCharacters(array $characters)
    {
        foreach ($characters as $str) {
            if (1 != strlen($str)) {
                throw new InvalidArgumentException(sprintf('The submitted string %s must be a single character', $str));
            }
        }
        return $characters;
    }
protected function filterSpecialCharacters ( array $ characters ) { foreach ( $ characters as $ str ) { if ( 1 != strlen ( $ str ) ) { throw new InvalidArgumentException ( sprintf ( 'The submitted string %s must be a single character' , $ str ) ) ; } } return $ characters ; }
Filter submitted special characters.

@param string[] $characters

@throws InvalidArgumentException if the string is not a single character

@return string[]
Filter submitted special characters .