src/SigningString.php
private function headerValue($name)
    {
        if ($this->message->hasHeader($name)) {
            $header = $this->message->getHeader($name);

            return end($header);
        } else {
            throw new SignedHeaderNotPresentException("Header '$name' not in message");
        }
    }
private function headerValue($name)
    {
        if ($this->message->hasHeader($name)) {
            $header = $this->message->getHeader($name);

            return end($header);
        } else {
            throw new SignedHeaderNotPresentException("Header '$name' not in message");
        }
    }
@param string $name

@return string

@throws SignedHeaderNotPresentException