public function __toString() : string
{
$string = '';
$string .= 'function ' . $this->getName();
$string .= '(' . implode(', ', $this->getParameterList()) . ')';
if (!$this->getUnionType()->isEmpty()) {
$string .= ' : ' . (string) $this->getUnionType();
}
$string .= ';';
return $string;
}