diff --git a/src/openalea/mtg/interface/mtg.py b/src/openalea/mtg/interface/mtg.py
index ebc27ce..7932bb7 100644
--- a/src/openalea/mtg/interface/mtg.py
+++ b/src/openalea/mtg/interface/mtg.py
@@ -18,7 +18,7 @@
 This module provides multiscale tree concepts to form MTG interface.
 """
 
-class MultiscaleTreeConcept(object):
+class MultiscaleTreeConcept():
     """
     Multiscale Tree Graph definition.
     """
diff --git a/src/openalea/mtg/io.py b/src/openalea/mtg/io.py
index 69e8cf3..eaf98d1 100644
--- a/src/openalea/mtg/io.py
+++ b/src/openalea/mtg/io.py
@@ -130,14 +130,17 @@ def get_properties(name,vid=None, time=False):
                         args[k] = klass(v)
                     except:
                         if vid is not None:
+                            if k =='_line':
+                                continue
                             print('Args ', v, 'of vertex ', vid, 'of type ', k, 'is not of type ', str(klass))
                         else:
                             print('Args ', v, 'of type ', k, 'is not of type ', str(klass))
         return args
 
     def add_dynamic_properties(mtg, vid, args):
-        print("Existing properties at ", vid, " ", mtg.get_vertex_property(vid))
-        print("New property: ", args)
+        if mtg.verbose:
+            log("Existing properties at ", vid, " ", mtg.get_vertex_property(vid))
+            log("New property: ", args)
 
         # a property can be a list but not a timeserie.
         # Create a real timeserie object...
@@ -167,7 +170,7 @@ def add_dynamic_properties(mtg, vid, args):
     implicit_scale = bool(symbol_at_scale)
 
     if debug:
-        print(list(symbol_at_scale.keys()))
+        log(list(symbol_at_scale.keys()))
 
     mtg = mtg if mtg else MTG()
 
@@ -234,7 +237,7 @@ def add_dynamic_properties(mtg, vid, args):
             scale = mtg.scale(vid)
         elif tag == '*':
             args = get_properties(name, vid=vid, time=True)
-            print(vid, '*(', args, ')')
+            log(vid, '*(', args, ')')
             # CPL Manage Dynamic_MTG
             add_dynamic_properties(mtg, vid, args)
         else:
@@ -252,7 +255,7 @@ def add_dynamic_properties(mtg, vid, args):
                 try:
                     new_scale = symbol_at_scale[symbol_class]
                 except:
-                    print('NODE ',node, bool(tag=='*'))
+                    print('NODE ',symbol_class, node, tag, bool(tag=='*'))
                 if tag == '/' and new_scale <= scale:
                     new_scale -= 1
                     pending_edge = '/'
@@ -457,7 +460,7 @@ def transform(turtle, mesh):
                     current_vertex = vid
                     pending_edge = ''
 
-                    log('','Cas 1.1', scale,
+                    log('','Case 1.1', scale,
                         'mtg.scale(vid)', mtg.scale(vid),
                         'generated vertex', vid)
 
@@ -467,7 +470,7 @@ def transform(turtle, mesh):
                     current_vertex = mtg.add_child(current_vertex,
                                                    edge_type=edge_type,
                                                    label=name)
-                    log('', 'Cas 1.2', scale,
+                    log('', 'Case 1.2', scale,
                         'mtg.scale(vid)', mtg.scale(vid),
                         'generated vertex', current_vertex)
                     assert mtg.scale(current_vertex) == module_scale
@@ -481,7 +484,7 @@ def transform(turtle, mesh):
                         assert vid == current_vertex
                         vid = mtg.add_component(vid)
                         current_vertex = vid
-                        log('', '', 'Cas 2.1', scale, 'generate new component', current_vertex)
+                        log('', '', 'Case 2.1', scale, 'generate new component', current_vertex)
                         scale += 1
                         if module_scale == scale:
                             assert mtg.scale(current_vertex) == module_scale
@@ -893,7 +896,7 @@ class Reader(object):
     The code contains topology relations and properties.
     """
 
-    def __init__(self, string, has_line_as_param=True, mtg=None, has_date=False):
+    def __init__(self, string, has_line_as_param=True, mtg=None, has_date=False, verbose=True):
         self.mtg = mtg
 
         # First implementation.
@@ -912,14 +915,17 @@ def __init__(self, string, has_line_as_param=True, mtg=None, has_date=False):
         self._no_line = 0
         self.warnings = []
         self.has_line_as_param = has_line_as_param
+        self.verbose = verbose
 
     def parse(self):
-        """
+        """ Read the header and parse the code.
         """
         self.header()
         self.code()
 
-        self.errors()
+        if self.verbose:
+            self.errors()
+        
         return self.mtg
 
     def header(self):
@@ -1120,6 +1126,7 @@ def errors(self):
                 print(warning)
             else:
                 print(id, " ", warning)
+    
     ############################################################################
     ### Parsing of the MTG code
     ### That's the real stuff...
@@ -1270,7 +1277,7 @@ def build_mtg(self):
         self.mtg = multiscale_edit(self._new_code, self._symbols, self._features, self.has_date, mtg=self.mtg)
         #self.mtg = multiscale_edit(self._new_code, {}, self._features)
 
-def read_mtg(s, mtg=None, has_date=False):
+def read_mtg(s, mtg=None, has_date=False, verbose=True):
     """ Create an MTG from its string representation in the MTG format.
 
     :Parameter:
@@ -1290,11 +1297,11 @@ def read_mtg(s, mtg=None, has_date=False):
     .. seealso:: :func:`read_mtg_file`.
 
     """
-    reader = Reader(s, mtg=mtg, has_date=has_date)
+    reader = Reader(s, mtg=mtg, has_date=has_date, verbose=verbose)
     g = reader.parse()
     return g
 
-def read_mtg_file(fn, mtg=None, has_date=False):
+def read_mtg_file(fn, mtg=None, has_date=False, verbose=True):
     """ Create an MTG from a filename.
 
     :Usage:
@@ -1306,7 +1313,7 @@ def read_mtg_file(fn, mtg=None, has_date=False):
     f = open(fn)
     txt = f.read()
     f.close()
-    return read_mtg(txt, mtg=mtg, has_date=has_date)
+    return read_mtg(txt, mtg=mtg, has_date=has_date, verbose=verbose)
 
 
 def mtg_display(g, vtx_id, tab='  ', edge_type=None, label=None):
diff --git a/src/openalea/mtg/mtg.py b/src/openalea/mtg/mtg.py
index b330c64..8063a06 100644
--- a/src/openalea/mtg/mtg.py
+++ b/src/openalea/mtg/mtg.py
@@ -67,7 +67,7 @@ class MTG(PropertyTree):
 
     '''
 
-    def __init__(self, filename='', has_date=False):
+    def __init__(self, filename='', has_date=False, verbose=False):
         ''' Create a new MTG object.
 
         :Usage:
@@ -78,6 +78,8 @@ def __init__(self, filename='', has_date=False):
 
         super(MTG, self).__init__()
 
+        self.verbose = verbose
+
         # Map a vid to its scale
         self._scale = {0:0}
 
@@ -93,7 +95,9 @@ def __init__(self, filename='', has_date=False):
 
         if filename:
             from .io import read_mtg_file
-            self = read_mtg_file(filename, mtg=self, has_date=has_date)
+            self = read_mtg_file(filename, mtg=self, has_date=has_date, verbose=verbose)
+
+        
 
     def __getitem__(self, vtx_id):
         """A simple getitem to extract relevant information on a vertex.
@@ -2389,7 +2393,8 @@ def _compute_missing_edges(mtg, scale, edge_type_property=None):
     for vid in roots:
         components = mtg._components.get(vid)
         if components is None:
-            print('ERROR: Missing component for vertex %d'%vid)
+            if mtg.verbose: 
+                print('ERROR: Missing component for vertex %d'%vid)
             continue
         #assert len(components) == 1
         cid = components[0]
@@ -2398,7 +2403,8 @@ def _compute_missing_edges(mtg, scale, edge_type_property=None):
         parent_id = mtg.complex(mtg.parent(cid))
         if parent_id is None:
             #roots.append(vid)
-            print('ERROR: Missing parent for vertex %d'%cid)
+            if mtg.verbose:
+                print('ERROR: Missing parent for vertex %d'%cid)
             continue
         if edge_type_property:
             edge_type = edge_type_property.get(cid)
@@ -2753,7 +2759,7 @@ def new_f(self, *args, **kwds):
     new_f.__doc__ = mtg_f.__doc__
     return new_f
 
-class _ProxyNode(object):
+class _ProxyNode():
     def __init__(self, g, vid):
         self.__dict__['_g'] = g
         self.__dict__['_vid'] = vid
diff --git a/src/openalea/mtg/plantframe/dresser.py b/src/openalea/mtg/plantframe/dresser.py
index 5267218..5bef0e4 100644
--- a/src/openalea/mtg/plantframe/dresser.py
+++ b/src/openalea/mtg/plantframe/dresser.py
@@ -43,7 +43,7 @@
 import os
 from openalea.plantgl.scenegraph import AmapSymbol
 
-class DressingData(object):
+class DressingData():
     """ Data and default geometric parameters.
 
     The dressing data are the default data that are used to define 
@@ -205,7 +205,7 @@ def dressing_data(file):
 
 ###############################################################
 ## Define the parser which is just a dict from keyword to a function 
-class Reader(object):
+class Reader():
     def __init__(self, dresser):
         self.dresser = dresser
         
diff --git a/src/openalea/mtg/plantframe/frame.py b/src/openalea/mtg/plantframe/frame.py
index 893780e..ff41431 100644
--- a/src/openalea/mtg/plantframe/frame.py
+++ b/src/openalea/mtg/plantframe/frame.py
@@ -34,7 +34,7 @@
 
 
 
-class Frame(object):
+class Frame():
     """ Frame representing geometric variables of each topologic elements.
     
     A frame is used to have a common representation of the geometric information 
@@ -137,7 +137,7 @@ def get_top_radius(self):
     top_radius = property(get_top_radius, set_top_radius, 'top_radius of the Frame')
 
 
-class AxialFrames(object):
+class AxialFrames():
     ''' Solve continuity constraints on an axis, i.e. a set of frames.
 
     '''
@@ -145,7 +145,7 @@ class AxialFrames(object):
 
 
 
-class PlantFrame(object):
+class PlantFrame():
     ''' Engine to compute the geometry of a plant based on 
     its topological description and parameters.
     '''
diff --git a/src/openalea/mtg/plantframe/plantframe.py b/src/openalea/mtg/plantframe/plantframe.py
index 66d221b..c35c8cd 100644
--- a/src/openalea/mtg/plantframe/plantframe.py
+++ b/src/openalea/mtg/plantframe/plantframe.py
@@ -56,7 +56,7 @@
 error = True
 epsilon = 1e-5
 
-class PlantFrame(object):
+class PlantFrame():
     ''' Engine to compute the geometry of a plant based on
     its topological description and parameters.
     '''
diff --git a/src/openalea/mtg/rewriting.py b/src/openalea/mtg/rewriting.py
index 0dd566f..c41dda1 100644
--- a/src/openalea/mtg/rewriting.py
+++ b/src/openalea/mtg/rewriting.py
@@ -20,7 +20,7 @@
 
 #### Module declaration #######
 
-class Module(object):
+class Module():
     def __init__(self, name, scale, **parameters):
         self.name = name
         self.scale = scale
@@ -299,7 +299,7 @@ def interpretation(f):
 
 eForward, eBackward = 1,0
 
-class MTGLsystem(object):
+class MTGLsystem():
     rules = dict()
 
     def __init__(self):
diff --git a/src/openalea/mtg/traversal.py b/src/openalea/mtg/traversal.py
index 4b9f2f0..c0d7d2e 100644
--- a/src/openalea/mtg/traversal.py
+++ b/src/openalea/mtg/traversal.py
@@ -271,7 +271,7 @@ def traverse_tree(tree, vtx_id, visitor):
   yield visitor.post_order(vtx_id)
 
 
-class Visitor(object):
+class Visitor():
   ''' Used during a tree traversal. '''
 
   def pre_order(self, vtx_id): 
diff --git a/src/openalea/mtg/tree.py b/src/openalea/mtg/tree.py
index dd2d66a..faad5c0 100644
--- a/src/openalea/mtg/tree.py
+++ b/src/openalea/mtg/tree.py
@@ -43,7 +43,7 @@ class InvalidVertex (GraphError, KeyError) :
     exception raised when a wrong vertex id is provided
     """
 
-class Tree(object):
+class Tree():
     '''
     Implementation of a rooted :class:`Tree`, 
     with methods to add and remove vertex.
diff --git a/src/openalea/mtg/version.py b/src/openalea/mtg/version.py
index 15d5f2e..5429bda 100644
--- a/src/openalea/mtg/version.py
+++ b/src/openalea/mtg/version.py
@@ -7,7 +7,7 @@
 minor = 2
 """(int) Version minor component."""
 
-post = 0
+post = 1
 """(int) Version post or bugfix component."""
 
 __version__ = ".".join([str(s) for s in (major, minor, post)])