code: def evaluate(self, node: InstanceNode) -> XPathValue:
          
          return self._eval(XPathContext(node, node, 1, 1))
docs: Evaluate the receiver and return the result.
  
          Args:
              node: Context node for XPath evaluation.
  
          Raises:
              XPathTypeError: If a subexpression of the receiver is of a wrong
                  type.