crete py file in your module

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

WARNING_TYPES = [('warning','Warning'),('info','Information'),('error','Error')]

class warning(osv.osv_memory):
_name = 'warning'
_description = 'warning'
_columns = {
    'type': fields.selection(WARNING_TYPES, string='Type', readonly=True),
    'title': fields.char(string="Title", size=100, readonly=True),
    'message': fields.text(string="Message", readonly=True),
}
_req_name = 'title'

def _get_view_id(self, cr, uid):
    """Get the view id
    @return: view id, or False if no view found
    """
    res = self.pool.get('ir.model.data').get_object_reference(cr, uid, 
        'osc_integ', 'warning_form')
    return res and res[1] or False

def message(self, cr, uid, id, context):
    message = self.browse(cr, uid, id)
    message_type = [t[1]for t in WARNING_TYPES if message.type == t[0]][0]
    print '%s: %s' % (_(message_type), _(message.title))
    res = {
        'name': '%s: %s' % (_(message_type), _(message.title)),
        'view_type': 'form',
        'view_mode': 'form',
        'view_id': self._get_view_id(cr, uid),
        'res_model': 'warning',
        'domain': [],
        'context': context,
        'type': 'ir.actions.act_window',
        'target': 'new',
        'res_id': message.id
    }
    return res

def warning(self, cr, uid, title, message, context=None):
    id = self.create(cr, uid, {'title': title, 'message': message, 'type': 'warning'})
    res = self.message(cr, uid, id, context)
    return res

def info(self, cr, uid, title, message, context=None):
    id = self.create(cr, uid, {'title': title, 'message': message, 'type': 'info'})
    res = self.message(cr, uid, id, context)
    return res

def error(self, cr, uid, title, message, context=None):
    id = self.create(cr, uid, {'title': title, 'message': message, 'type': 'error'})
    res = self.message(cr, uid, id, context)
    return res

and create xml file

<openerp>
   <data>
    <record id="warning_form" model="ir.ui.view">
        <field name="name">warning.form</field>
        <field name="model">warning</field>
        <field eval="20" name="priority"/>
        <field name="arch" type="xml">
            <form string="Warning" version="7.0">
                <field name="message"  nolabel="1" />
                <footer>
                    <button string="OK" class="oe_highlight" special="cancel" />
                </footer>
            </form>
        </field>
    </record>

    <record model="ir.actions.act_window" id="action_warning">
        <field name="name">Warning</field>
        <field name="res_model">warning</field>
        <field name="view_type">form</field>
        <field name="view_mode">form</field>
        <field name="view_id" ref="warning_form" />
        <field name="target">new</field>
    </record>
</data>

</openerp>

and finally call the method

return self.pool.get('warning').info(cr, uid, title='Export imformation', message="%s products Created, %s products Updated "%(str(prod_new),str(prod_update)))