diff --git a/etesian/src/EtesianEngine.cpp b/etesian/src/EtesianEngine.cpp
index 6fd8a41b..32120a88 100644
--- a/etesian/src/EtesianEngine.cpp
+++ b/etesian/src/EtesianEngine.cpp
@@ -646,6 +646,9 @@ namespace Etesian {
 
             _cellsToIds.insert( make_pair(getString(instance->getName()),instanceId) );
             _idsToInsts.push_back( instance );
+            // cerr << "FIXED id=" << instanceId
+            //      << " " << instance << " size:(" << xsize << " " << ysize
+            //      << ") pos:(" << xpos << " " << ypos << ")" << endl;
             ++instanceId;
             dots.dot();
           }
@@ -710,8 +713,9 @@ namespace Etesian {
                                           |coloquinte::YFlippable;
       } else {
         instances[instanceId].attributes = 0;
-      //cerr << "FIXED: " << instance << " size:(" << xsize << " " << ysize
-      //      << ") pos:(" << xpos << " " << ypos << ")" << endl;
+        // cerr << "FIXED id=" << instanceId
+        //      << " " << instance << " size:(" << xsize << " " << ysize
+        //      << ") pos:(" << xpos << " " << ypos << ")" << endl;
       }
 
       _cellsToIds.insert( make_pair(instanceName,instanceId) );
diff --git a/hurricane/src/hurricane/Plug.cpp b/hurricane/src/hurricane/Plug.cpp
index 147e6569..9fd814fe 100644
--- a/hurricane/src/hurricane/Plug.cpp
+++ b/hurricane/src/hurricane/Plug.cpp
@@ -137,7 +137,7 @@ void Plug::setNet(Net* net)
   if (net != getNet()) {
     if (net and (getCell() != net->getCell()))
       throw Error( "Plug::setNet(): Can't set Net of plug %s to %s\n"
-                   "Net belong to %s instead of %s."
+                   "Net belong to %s while plug belong to of %s."
                  , getString(this).c_str()
                  , getString(net).c_str()
                  , getString(net->getCell()).c_str()
diff --git a/hurricane/src/isobar/PyCell.cpp b/hurricane/src/isobar/PyCell.cpp
index 81726393..df3aecdb 100644
--- a/hurricane/src/isobar/PyCell.cpp
+++ b/hurricane/src/isobar/PyCell.cpp
@@ -708,6 +708,39 @@ extern "C" {
   }
 
 
+  static PyObject* PyCell_flattenNets ( PyCell* self, PyObject *args )
+  {
+    cdebug_log(20,0) << "PyCell_flattenNets()" << endl;
+    
+    Instance* instance = NULL;
+    PyObject* arg0     = NULL;
+    PyObject* arg1     = NULL;
+
+    HTRY
+      METHOD_HEAD ( "Cell.flattenNets()" )
+      __cs.init( "Cell.flattenNets" );
+      if (not PyArg_ParseTuple(args,"O&O&:Cell.flattenNets"
+                              ,Converter,&arg0
+                              ,Converter,&arg1
+                              )) {
+          PyErr_SetString( ConstructorError, "Cell.flattenNets(): Takes exactly two parameters." );
+          return NULL;
+      }
+  
+      if (arg0 == Py_None) {
+        cell->flattenNets( NULL, PyInt_AsLong(arg1) );
+      } else if (__cs.getObjectIds() == ":ent:int") {
+        cell->flattenNets( PYINSTANCE_O(arg0), PyInt_AsLong(arg1) );
+      } else {
+        string message = "Cell.flattenNets(): Bad type of parameter(s), \"" + __cs.getObjectIds() + "\".";
+        PyErr_SetString( ConstructorError, message.c_str() );
+        return NULL;
+      }
+    HCATCH
+    Py_RETURN_NONE;
+  }
+
+
   // ---------------------------------------------------------------
   // Attribute Method  :  "PyCell_destroyPhysical ()"
 
@@ -778,6 +811,7 @@ extern "C" {
     , { "setRouted"           , (PyCFunction)PyCell_setRouted           , METH_VARARGS, "Sets the cell routed status." }
     , { "uniquify"            , (PyCFunction)PyCell_uniquify            , METH_VARARGS, "Uniquify the Cell and it's instances up to <depth>." }
     , { "getClone"            , (PyCFunction)PyCell_getClone            , METH_NOARGS , "Return a copy of the Cell (placement only)." }
+    , { "flattenNets"         , (PyCFunction)PyCell_flattenNets         , METH_VARARGS, "Perform a virtual flatten, possibly limited to one instance." }
     , { "destroyPhysical"     , (PyCFunction)PyCell_destroyPhysical     , METH_NOARGS , "Destroy all physical components, including DeepNets (vflatten)." }
     , { "destroy"             , (PyCFunction)PyCell_destroy             , METH_NOARGS , "Destroy associated hurricane object The python object remains." }
     , {NULL, NULL, 0, NULL}   /* sentinel */
@@ -804,6 +838,18 @@ extern "C" {
   PyTypeInheritedObjectDefinitions(Cell, Entity)
 
 
+  extern  void  PyCell_postModuleInit ()
+  {
+    PyObject* constant;
+
+    LoadObjectConstant(PyTypeCell.tp_dict,Cell::Flags::NoFlags         ,"Flags_NoFlags");
+    LoadObjectConstant(PyTypeCell.tp_dict,Cell::Flags::BuildRings      ,"Flags_BuildRings");
+    LoadObjectConstant(PyTypeCell.tp_dict,Cell::Flags::BuildClockRings ,"Flags_BuildClockRings");
+    LoadObjectConstant(PyTypeCell.tp_dict,Cell::Flags::BuildSupplyRings,"Flags_BuildSupplyRings");
+    LoadObjectConstant(PyTypeCell.tp_dict,Cell::Flags::NoClockFlatten  ,"Flags_NoClockFlatten");
+  }
+
+
 #endif  // End of Shared Library Code Part.
 
 
diff --git a/hurricane/src/isobar/PyHurricane.cpp b/hurricane/src/isobar/PyHurricane.cpp
index 4166dbbe..8a7b0706 100644
--- a/hurricane/src/isobar/PyHurricane.cpp
+++ b/hurricane/src/isobar/PyHurricane.cpp
@@ -872,6 +872,7 @@ extern "C" {
     PyRoutingPad_postModuleInit();
     PyNet_postModuleInit();
     PyNetRoutingState_postModuleInit();
+    PyCell_postModuleInit();
     PyInstance_postModuleInit();
     PyQuery_postModuleInit();
 
diff --git a/hurricane/src/isobar/hurricane/isobar/PyCell.h b/hurricane/src/isobar/hurricane/isobar/PyCell.h
index 928fa5b5..7f49612d 100644
--- a/hurricane/src/isobar/hurricane/isobar/PyCell.h
+++ b/hurricane/src/isobar/hurricane/isobar/PyCell.h
@@ -1,7 +1,7 @@
 // -*- C++ -*-
 //
 // This file is part of the Coriolis Software.
-// Copyright (c) UPMC 2006-2018, All Rights Reserved
+// Copyright (c) UPMC 2006-2020, All Rights Reserved
 //
 // +-----------------------------------------------------------------+ 
 // |                   C O R I O L I S                               |
@@ -14,9 +14,7 @@
 // +-----------------------------------------------------------------+
 
 
-#ifndef PY_CELL_H
-#define PY_CELL_H
-
+#pragma  once
 #include "hurricane/isobar/PyEntity.h"
 #include "hurricane/Cell.h"
 
@@ -40,8 +38,9 @@ namespace  Isobar {
     extern  PyTypeObject  PyTypeCell;
     extern  PyMethodDef   PyCell_Methods[];
 
-    extern  PyObject* PyCell_Link       ( Hurricane::Cell* object );
-    extern  void      PyCell_LinkPyType ();
+    extern  PyObject* PyCell_Link           ( Hurricane::Cell* object );
+    extern  void      PyCell_LinkPyType     ();
+    extern  void      PyCell_postModuleInit ();
   
 
 #define IsPyCell(v)    ((v)->ob_type == &PyTypeCell)
@@ -52,5 +51,3 @@ namespace  Isobar {
   }  // extern "C".
 
 }  // Isobar namespace.
- 
-#endif  // PY_CELL_H