ImportMultilayer: add/simplify file header

PyCore/Sample/ImportMultiLayer.cpp

+//  ************************************************************************************************
+//
+//  BornAgain: simulate and fit reflection and scattering
+//
+//! @file      PyCore/Sample/ImportMultiLayer.h
+//! @brief     Implements createMultiLayerFromPython.
+//!
+//! @homepage  http://www.bornagainproject.org
+//! @license   GNU General Public License v3 or higher (see COPYING)
+//! @copyright Forschungszentrum Jülich GmbH 2018
+//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
+//
+//  ************************************************************************************************
+
 #ifdef BORNAGAIN_PYTHON
 
 #include "ImportMultiLayer.h"
@@ -18,11 +32,10 @@ PyObjectPtr createMultiLayerFromPython(void*& multilayer_ptr, const std::string&
 
     // locate the `get_simulation` function (it is an attribute of the module)
     PyObject* pAddFn = PyObject_GetAttrString(tmpModule.get(), functionName.c_str());
-    if (!pAddFn) {
+    if (!pAddFn)
         throw std::runtime_error(errorDescription("PyInterpreter::BornAgain: "
                                                   "Cannot locate the compiled function '"
                                                   + functionName + "'"));
-    }
 
     // create a `MultiLayer` Python object via calling the function
     PyObject* instance = PyObject_CallFunctionObjArgs(pAddFn, NULL);
@@ -30,10 +43,9 @@ PyObjectPtr createMultiLayerFromPython(void*& multilayer_ptr, const std::string&
     // clean up
     Py_DecRef(pAddFn);
 
-    if (!instance) {
+    if (!instance)
         throw std::runtime_error(errorDescription(
             "PyInterpreter::BornAgain: Cannot call the function '" + functionName + "'"));
-    }
 
     // Construct a C++ object from the Python object
     /* NOTE:

PyCore/Sample/ImportMultiLayer.h

@@ -3,7 +3,7 @@
 //  BornAgain: simulate and fit reflection and scattering
 //
 //! @file      PyCore/Sample/ImportMultiLayer.h
-//! @brief     Forward declaration for createMultiLayerFromPython.
+//! @brief     Declares createMultiLayerFromPython.
 //!
 //! @homepage  http://www.bornagainproject.org
 //! @license   GNU General Public License v3 or higher (see COPYING)
@@ -12,12 +12,11 @@
 //
 //  ************************************************************************************************
 
-#ifndef BORNAGAIN_PYCORE_SAMPLE_IMPORTMULTILAYER_H
-#define BORNAGAIN_PYCORE_SAMPLE_IMPORTMULTILAYER_H
-
 #ifdef SWIG
 #error no need to expose this header to Swig
 #endif
+#ifndef BORNAGAIN_PYCORE_SAMPLE_IMPORTMULTILAYER_H
+#define BORNAGAIN_PYCORE_SAMPLE_IMPORTMULTILAYER_H
 
 #include "PyCore/Embed/PyObjectPtr.h"
 #include <string>