internal: allow Response.DecodeProp to decode multiple values

internal/elements.go

@@ -131,7 +131,8 @@ func IsMissingProp(err error) bool {
 	return ok
 }
 
-func (resp *Response) DecodeProp(v interface{}) error {
+func (resp *Response) DecodeProp(values ...interface{}) error {
+	for _, v := range values {
 		// TODO wrap errors with more context (XML name)
 		name, err := valueXMLName(v)
 		if err != nil {
@@ -151,6 +152,9 @@ func (resp *Response) DecodeProp(v interface{}) error {
 			return raw.Decode(v)
 		}
 		return &missingPropError{name}
+	}
+
+	return nil
 }
 
 func (resp *Response) EncodeProp(code int, v interface{}) error {