+#include "SketchPlugin_Sketch.h"
+#include <ModelAPI_Document.h>
+#include <ModelAPI_Data.h>
+#include <ModelAPI_Object.h>
+#include <ModelAPI_ResultConstruction.h>
+
+/// It is important.
+///
+/// Before writing a new method implementation in this file, please check the next rule:
+/// exported public methods must not be implemented in this source file. They should be inline and
+/// placed in the header file.
+/// Because it leads to the runtime problem on the Linux OS.
+///
+/// The reason is that this is an abstract interface. An interface of this class can be used in
+/// outside libraries through casting without a link to the current library.