Hi friendz,

          When sending the mail by clicking button "send by Email" in "addition" module,  the following error comes:
          AttributeError: 'addition' object has no attribute 'message_post'

__openerp__.py:

{
    "name": "addition",
    "version": "7.0",
    "summary" : "addition of 2 nos",
    "depends": ["base","mail","email_template"],
    "author": "atchuthan",
    "category": "Others",
    "description": """
    This module provide : summation of 2 integer numbers  
    """,
     'data' : ['addition_view.xml','addition_action_data.xml'],
    'demo_xml': [],
    'installable': True,
    'auto-install' : True,
    'active': False
}

addition.py:

from osv import osv, fields
from openerp.tools.translate import _

class addition(osv.osv):
    _name = 'addition' 
    _rec_name = 'result'  
    _columns = {
            'number1': fields.integer('number 1', required=True),
            'number2' : fields.integer('number 2', required=True),
            'result' : fields.integer('Result'),
                    }

    def action_addition_send(self, cr, uid, ids, context=None):
            '''
            This function opens a window to compose an email, with the edi sale template message loaded by default
            '''
            assert len(ids) == 1, 'This option should only be used for a single id at a time.'
            ir_model_data = self.pool.get('ir.model.data')
            try:
                template_id = ir_model_data.get_object_reference(cr, uid, 'addition', 'email_template_edi_addition')[1]
            except ValueError:
                template_id = False
            try:
                compose_form_id = ir_model_data.get_object_reference(cr, uid, 'mail', 'email_compose_message_wizard_form')[1]
            except ValueError:
                compose_form_id = False 
            ctx = dict(context)
            ctx.update({
                'default_model': 'addition',
                'default_res_id': ids[0],
                'default_use_template': bool(template_id),
                'default_template_id': template_id,
                'default_composition_mode': 'comment',
                'mark_so_as_sent': True
            })
            return {
                'type': 'ir.actions.act_window',
                'view_type': 'form',
                'view_mode': 'form',
                'res_model': 'mail.compose.message',
                'views': [(compose_form_id, 'form')],
                'view_id': compose_form_id,
                'target': 'new',
                'context': ctx,
            }

class mail_compose_message(osv.Model):
    _inherit = 'mail.compose.message'

    def send_mail(self, cr, uid, ids, context=None):
        context = context or {}
        if context.get('default_model') == 'addition' and context.get('default_res_id') and context.get('mark_so_as_sent'):
            context = dict(context, mail_post_autofollow=True)
        return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)

addition_view.xml:

<?xml version="1.0" encoding="utf-8" ?>
<openerp>
    <data>
        <record model="ir.ui.view" id="addition_tree_view">
            <field name="name">addition.tree</field>
            <field name="model">addition</field>
            <field name="type">tree</field>
            <field name="arch" type="xml">
                <tree string="addition_tree">
                    <field name="number1" />
                    <field name="number2" />
                    <field name="result" />
                </tree>
            </field>
        </record>
        <record model="ir.ui.view" id="addition_form_view">
            <field name="name">addition.form</field>
            <field name="model">addition</field>
            <field name="type">form</field>
            <field name="arch" type="xml">
                <form string="addition_form" version="7.0">
                    <header>
                        <button name="action_addition_send" string="Send by Email"
                            type="object" class="oe_highlight" />
                    </header>
                    <sheet>
                        <group>
                            <field name="number1" onchange="onchange_addition(number1, number2)" />
                            <field name="number2" onchange="onchange_addition(number1, number2)" />
                            <field name="result" />  <!-- onchange_addition(number1, number2) -->
                        </group>
                    </sheet>
                </form>
            </field>
        </record>
        <record model="ir.actions.act_window" id="action_addition_form">
            <field name="name">addition</field>
            <field name="res_model">addition</field>
        </record>
        <menuitem name="Parent" icon="terp-project" id="parent_id" />
        <menuitem name="Son" parent="parent_id" id="son_id" />
        <menuitem name="Addition" parent="son_id" id="addition_id"
            action="action_addition_form" />
    </data>
</openerp>

addition_action_data.xml:

<?xml version="1.0" ?>
<openerp>
    <data>
        <!-- EDI related Email Templates menu -->
        <record model="ir.actions.act_window" id="action_email_templates">
            <field name="name">Email Templates</field>
            <field name="res_model">email.template</field>
            <field name="view_type">form</field>
            <field name="view_mode">form,tree</field>
            <field name="view_id" ref="email_template.email_template_tree" />
            <field name="search_view_id" ref="email_template.view_email_template_search" />
            <field name="context"
                eval="{'search_default_model_id': ref('model_addition')}" />
        </record>
    </data>

    <!-- Mail template are declared in a NOUPDATE block so users can freely 
        customize/delete them -->
    <data noupdate="1">
        <!--Email template -->
        <record id="email_template_edi_addition" model="email.template">
            <field name="name">Addition 2 nos - Send by mail</field>
            <field name="email_from">bms@openerp.com</field>
            <field name="subject">addition</field>
            <field name="email_to">atchuthantu@yahoo.com</field>
            <field name="auto_delete" eval="True" />
            <field name="model_id" ref="model_addition" />
            <field name="body_html"><![CDATA[
<div style="font-family: 'Lucica Grande', Ubuntu, Arial, Verdana, sans-serif; font-size: 12px; color: rgb(34, 34, 34); background-color: #FFF; ">

    <p>Hello,</p>

    <p>Addition successful</p>

</div>
            ]]></field>
        </record>
    </data>
</openerp>

traceback:

2013-06-18 12:56:43,251 3505 INFO bms werkzeug: 127.0.0.1 - - [18/Jun/2013 12:56:43] "POST /web/dataset/call_kw/mail.compose.message:create HTTP/1.1" 200 -
2013-06-18 12:56:43,314 3505 INFO bms werkzeug: 127.0.0.1 - - [18/Jun/2013 12:56:43] "POST /web/dataset/call_kw/mail.compose.message:read HTTP/1.1" 200 -
2013-06-18 12:56:43,392 3505 INFO bms werkzeug: 127.0.0.1 - - [18/Jun/2013 12:56:43] "POST /web/dataset/call_kw/res.partner:name_get HTTP/1.1" 200 -
2013-06-18 12:56:43,418 3505 ERROR bms openerp.osv.osv: Uncaught exception
Traceback (most recent call last):
  File "/var/app/openerp/server/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/var/app/openerp/server/openerp/osv/osv.py", line 197, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/var/app/openerp/server/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/var/app/openerp/addons/bms/bms.py", line 304, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/addition/addition.py", line 55, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/email_template/wizard/mail_compose_message.py", line 80, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/mail/wizard/mail_compose_message.py", line 259, in send_mail
    msg_id = active_model_pool.message_post(cr, uid, [res_id], type='comment', subtype=subtype, context=context, **post_values)
AttributeError: 'addition' object has no attribute 'message_post'
2013-06-18 12:56:43,430 3505 ERROR bms openerp.netsvc: 'addition' object has no attribute 'message_post'
Traceback (most recent call last):
  File "/var/app/openerp/server/openerp/netsvc.py", line 293, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/var/app/openerp/server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File "/var/app/openerp/server/openerp/osv/osv.py", line 188, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/var/app/openerp/server/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/var/app/openerp/server/openerp/osv/osv.py", line 197, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/var/app/openerp/server/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/var/app/openerp/addons/bms/bms.py", line 304, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/addition/addition.py", line 55, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/email_template/wizard/mail_compose_message.py", line 80, in send_mail
    return super(mail_compose_message, self).send_mail(cr, uid, ids, context=context)
  File "/var/app/openerp/addons/mail/wizard/mail_compose_message.py", line 259, in send_mail
    msg_id = active_model_pool.message_post(cr, uid, [res_id], type='comment', subtype=subtype, context=context, **post_values)
AttributeError: 'addition' object has no attribute 'message_post'
2013-06-18 12:56:43,432 3505 INFO bms werkzeug: 127.0.0.1 - - [18/Jun/2013 12:56:43] "POST /web/dataset/call_button HTTP/1.1" 200 -