Step-1 Install the live chat (im_livechat) module.
Step-2 After that customize .py(Python file) file:
In below example, I have custmozied the .py file. You can directly paste below python code in your .py file.

class im_livechat_channel(osv.Model):
    _name = 'im_livechat.channel'

    def _get_default_image(self, cr, uid, context=None):
        image_path = openerp.modules.get_module_resource('im_livechat', 'static/src/img', 'default.png')
        return tools.image_resize_image_big(open(image_path, 'rb').read().encode('base64'))
    def _get_image(self, cr, uid, ids, name, args, context=None):
        result = dict.fromkeys(ids, False)
        for obj in self.browse(cr, uid, ids, context=context):
            result[obj.id] = tools.image_get_resized_images(obj.image)
        return result
    def _set_image(self, cr, uid, id, name, value, args, context=None):
        return self.write(cr, uid, [id], {'image': tools.image_resize_image_big(value)}, context=context)

    def _are_you_inside(self, cr, uid, ids, name, arg, context=None):
        res = {}
        for record in self.browse(cr, uid, ids, context=context):
            res[record.id] = False
            for user in record.user_ids:
                if user.id == uid:
                    res[record.id] = True
                    break
        return res

    def _script_external(self, cr, uid, ids, name, arg, context=None):
        values = {
            "url": self.pool.get('ir.config_parameter').get_param(cr, openerp.SUPERUSER_ID, 'web.base.url'),
            "dbname":cr.dbname
        }
        res = {}
        for record in self.browse(cr, uid, ids, context=context):
            values["channel"] = record.id
            res[record.id] = self.pool['ir.ui.view'].render(cr, uid, 'im_livechat.external_loader', values, context=context)
        return res

    def _script_internal(self, cr, uid, ids, name, arg, context=None):
        values = {
            "url": self.pool.get('ir.config_parameter').get_param(cr, openerp.SUPERUSER_ID, 'web.base.url'),
            "dbname":cr.dbname
        }
        res = {}
        for record in self.browse(cr, uid, ids, context=context):
            values["channel"] = record.id
            res[record.id] = self.pool['ir.ui.view'].render(cr, uid, 'im_livechat.internal_loader', values, context=context)
        return res

    def _web_page(self, cr, uid, ids, name, arg, context=None):
        res = {}
        for record in self.browse(cr, uid, ids, context=context):
            res[record.id] = self.pool.get('ir.config_parameter').get_param(cr, openerp.SUPERUSER_ID, 'web.base.url') + \
                "/im_livechat/support/%s/%i" % (cr.dbname, record.id)
        return res