Hi everyone,i try to update the module calendar.event and to link it with another class but when i try to open the calendar view relating to emploi.temps i have this error : TypeError: Invalid attribute dictionary: str and when i try to add a new meeting in the class professeur.entity i have a disorganized calendar view??any idea please

emploi.py

class professeur_entity(osv.osv):

_name = 'professeur.entity'
_columns = {
    'name': fields.char('Nom', required=True, size=32),
    'prenom': fields.char('Prenom', required=True, size=32),
    'emp_ids': fields.one2many('emploi.temps','professeur_id', 'Emploi'),
}

professeur_entity()

class emploi_temps(osv.osv):

_name = 'emploi.temps'
_inherit = 'calendar.event'
_columns = {
  'professeur_id': fields.many2one('professeur.entity','Professeur', required=True),
}

emploi_temps()

emploi_view.xml

enter code here<?xml version="1.0" encoding="utf-8"?>

<openerp> <data>

<!-- <menuitem name="Gestion Emploi" id="menu_principal"/>-->


<!--  ce menu est celui existant dans la barre en haut -->
<menuitem name="Gestion professeur" id="menu_prof"/>

<menuitem name="Enseignant" id="menu_prof1" parent="menu_prof"/>

<record model="ir.ui.view" id="view_school_prof_form">
    <field name="name">prof.form</field>
    <field name="model">professeur.entity</field>
    <field name="type">form</field>
    <field name="arch" type="xml">
       <form string="Enseignant"  version="7.0">
           <group col="4" colspan="6">       
               <field name="name"/>
               <field name="prenom"/>
               <field name="emp_ids" colspan="4" nolabel="1" />
            </group>

       </form>
    </field>
</record>   

    <record model="ir.ui.view" id="view_school_prof_tree">
    <field name="name">prof.tree</field>
    <field name="model">professeur.entity</field>
    <field name="type">tree</field>
    <field name="arch" type="xml">
        <tree string="Enseignants"  version="7.0">
               <field name="name"/>
               <field name="prenom"/>

       </tree>
    </field>
</record>

<record model="ir.actions.act_window" id="action_school_prof_form">
    <field name="name">Liste des enseignants</field>
    <field name="res_model">professeur.entity</field>
    <field name="view_type">form</field>
    <field name="view_mode">tree,form</field>
</record>

    <!--  Et finalement il y a le menu qui contient l'action pour ouvrir la vue tree de ton module -->

<menuitem action="action_school_prof_form" id="menu_prof2" parent="menu_prof1" />

<menuitem name="Emploi" parent="menu_prof" id="menu"/>

 <record model="ir.ui.view" id="event_form_view_inherit">
        <field name="name">emploi.temps.form</field>
        <field name="model">emploi.temps</field>
        <field name="inherit_id" ref="base_calendar.event_form_view"/>
        <field name="type">form</field>
        <field name="arch" type="xml">
            <field name="name" position="after">
      <field name="professeur_id" />

    </field>
        <field name="state" position="replace"/>
        </field>
    </record>


 <record model="ir.ui.view" id="event_tree_view_inherit">
        <field name="name">emploi.temps.tree</field>
        <field name="model">emploi.temps</field>
        <field name="inherit_id" ref="base_calendar.event_tree_view"/>
        <field name="type">tree</field>
        <field name="arch" type="xml">
            <field name="name" position="after">
      <field name="professeur_id" />
    </field>
        <field name="state" position="replace"/>
        </field>
    </record>


 <record model="ir.ui.view" id="event_calendar_view_inherit">
        <field name="name">emploi.temps.calendar</field>
        <field name="model">emploi.temps</field>
        <field name="inherit_id" ref="base_calendar.event_calendar_view"/>
        <field name="type">calendar</field>
        <field name="arch" type="xml">
          <calendar string="Events" date_start="date" color="show_as" date_delay="duration">
                <field name="name"/>
                <field name="class"/>
                <field name="show_as"/>
            </calendar>
        </field>
    </record>




     <record model="ir.actions.act_window" id="action_school_emploi_form">
    <field name="name">Emploi du temps</field>
    <field name="res_model">emploi.temps</field>
    <field name="view_type">form</field>
    <field name="view_mode">tree,form,calendar</field>
</record>

<menuitem name="Gestion d'emploi du temps" action="action_school_emploi_form" id="emploi" parent="menu" />

</data> </openerp>

#Traceback

OpenERP Server Error Client Traceback (most recent call last):
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\http.py", line 203, in dispatch
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\controllers\main.py", line 1129, in call_kw
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\controllers\main.py", line 1121, in _call_kw
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\session.py", line 43, in proxy
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\session.py", line 31, in proxy_method
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\session.py", line 104, in send

Server Traceback (most recent call last):
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server\openerp\addons\web\session.py", line 90, in send
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\netsvc.py", line 293, in dispatch_rpc
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\service\web_services.py", line 626, in dispatch
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\osv.py", line 188, in execute_kw
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\osv.py", line 131, in wrapper
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\osv.py", line 197, in execute
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\osv.py", line 185, in execute_cr
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\orm.py", line 2244, in fields_view_get
  File "C:\Program Files (x86)\OpenERP 7.0-20130409-232349\Server\server.\openerp\osv\orm.py", line 2010, in _get_default_calendar_view
  File "lxml.etree.pyx", line 2443, in lxml.etree.SubElement (src/lxml/lxml.etree.c:47341)
  File "apihelpers.pxi", line 204, in lxml.etree._makeSubElement (src/lxml/lxml.etree.c:11274)
  File "apihelpers.pxi", line 265, in lxml.etree._initNodeAttributes (src/lxml/lxml.etree.c:11823)
  TypeError: Invalid attribute dictionary: str