code: public JTSGeometryExpression<Geometry> symDifference(Expression<? extends Geometry> geometry) {
          return JTSGeometryExpressions.geometryOperation(SpatialOps.SYMDIFFERENCE, mixin, geometry);
      }
docs: Returns a geometric object that represents the
  Point set symmetric difference of this geometric object with anotherGeometry.
  
  @param geometry other geometry
  @return symmetric difference