code: public function parseLiteral($valueNode, ?array $variables = null)
      {
          if ($valueNode instanceof FloatValueNode || $valueNode instanceof IntValueNode) {
              return (float) $valueNode->value;
          }
  
          // Intentionally without message, as all information already in wrapped Exception
          throw new Exception();
      }
docs: @param Node         $valueNode
  @param mixed[]|null $variables
  
  @return float|null
  
  @throws Exception