src/Printable.php
private function arrayPair($key, $val): string
    {
        $key_str = is_int($key) ? $key : $this->quoted($key);

        $val_str = $this->arrayValue($val);

        return sprintf('%s => %s', $key_str, $val_str);
    }
private function arrayPair($key, $val): string
    {
        $key_str = is_int($key) ? $key : $this->quoted($key);

        $val_str = $this->arrayValue($val);

        return sprintf('%s => %s', $key_str, $val_str);
    }
Return a formatted string for the given key => value pair.

@param int|string    $key
@param mixed         $val
@return string