diff --git a/python/core/geometry/qgstriangle.sip b/python/core/geometry/qgstriangle.sip
index ee72c2ddc19..316f3f06915 100644
--- a/python/core/geometry/qgstriangle.sip
+++ b/python/core/geometry/qgstriangle.sip
@@ -68,10 +68,8 @@ class QgsTriangle : QgsPolygonV2
     virtual bool fromWkt( const QString &wkt );
 
 
-    QDomElement asGML3( QDomDocument &doc, int precision = 17, const QString &ns = "gml" ) const;
-%Docstring
- :rtype: QDomElement
-%End
+    virtual QDomElement asGML3( QDomDocument &doc, int precision = 17, const QString &ns = "gml" ) const;
+
 
     virtual QgsPolygonV2 *surfaceToPolygon() const /Factory/;
 
diff --git a/src/core/geometry/qgstriangle.h b/src/core/geometry/qgstriangle.h
index 969c320046e..378d8e5b81e 100644
--- a/src/core/geometry/qgstriangle.h
+++ b/src/core/geometry/qgstriangle.h
@@ -75,7 +75,7 @@ class CORE_EXPORT QgsTriangle : public QgsPolygonV2
 
     // inherited: QString asWkt( int precision = 17 ) const;
     // inherited (as a polygon): QDomElement asGML2( QDomDocument &doc, int precision = 17, const QString &ns = "gml" ) const;
-    QDomElement asGML3( QDomDocument &doc, int precision = 17, const QString &ns = "gml" ) const;
+    QDomElement asGML3( QDomDocument &doc, int precision = 17, const QString &ns = "gml" ) const override;
     // inherited: QString asJSON( int precision = 17 ) const;
 
     QgsPolygonV2 *surfaceToPolygon() const override SIP_FACTORY;