无法在openERP中导入自定义模块

我已经完成openerp了使用python和xml的简单定制模块。但我无法导入openerp。我的模块未显示在openerp中。

这是 __init__py

import os
os.environ['TZ'] = 'UTC' # Set the timezone...
import time              # ... *then* import time.
del os
del time

# The hard-coded super-user id (a.k.a. administrator, or root user).
SUPERUSER_ID = 1

import addons
import cli
import conf
import loglevels
import modules
import netsvc
import osv
import pooler
import release
import report
import service
import sql_db
import tools
import workflow
import sim
# backward compatilbility
# TODO: This is for the web addons, can be removed later.
wsgi = service
wsgi.register_wsgi_handler = wsgi.wsgi_server.register_wsgi_handler
# Is the server running in multi-process mode (e.g. behind Gunicorn).
# If this is True, the processes have to communicate some events,
# e.g. database update or cache invalidation. Each process has also
# its own copy of the data structure and we don't need to care about
# locks between threads.
multi_process = False

# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:

这是 __openerp__.py

{
'name': 'Student Information Management',
'version': '0.1',
'category': 'Tools',
'description': """This module is for the Student Information Management.""",
'author': 'Mir Nauman Tahir',
'website': 'http://mirnauman.wordpress.com/',
'depends': ['base'],
'init_xml': [],
'update_xml': ['sim_view.xml'],
'demo_xml': [],
'installable': True,
'active': True,

}

这是sim_view.xml

<?xml version="1.0"?>
<openerp>
<data>
<!-- ============== student================= -->
<!-- 1st part of the sim_view start-->
<record model="ir.ui.view" id="student_form">
<field name="name">Student</field>
<field name="model">sim.student</field>
<field name="type">form</field>
<field name="arch" type="xml">
<form string="Student" version="7.0">
<field name="name"/>
<field name="student_name"/>
<field name="father_name"/>
<field name="gender"/>
<field name="contact_no"/>
</form>
</field>
</record>
<!-- 1st part of the sim_view end-->
<!--2nd part of the sim_view start-->
<record model="ir.ui.view" id="student_tree">
<field name="name">Student</field>
<field name="model">sim.student</field>
<field name="type">tree</field>
<field name="arch" type="xml">
<tree string="Student">
<field name="name"/>
<field name="student_name"/>
<field name="father_name"/>
<field name="gender"/>
<field name="contact_no"/>
</tree>
</field>
</record>
<!--2nd part of the sim_view end-->
<!-- 3rd part of the sim_view start-->
<record model="ir.actions.act_window" id="action_student">
<field name="name">Student</field>
<field name="res_model">sim.student</field>
<field name="view_type">form</field>
<field name="view_mode">tree,form</field>
</record>
<!--3rd part of the sim_view end-->
<!--4th part of the sim_view start-->
<menuitem&nbsp;name="SIM/Student/StudentInfo" id="menu_sim_student" action="action_student"/>
<!--4th part of the sim_view end-->
</data>
</openerp>

这个sim.py

from openerp.osv import fields

class student(osv.osv):
    _name = "sim.student"
    _description = "This table is for keeping personal data of student"
    _columns = {
        'name': fields.char('Registration Number',size=256,required=True),
        'student_name': fields.char('Student Name',size=256,required=True),
        'father_name': fields.char('Father Name',size=256),
        'gender':fields.selection([('male','Male'),('female','Female')],'Gender'),
        'contact_no':fields.char('Contact Number',size=256)
    }
student()

我在openerp中看不到我的模块。我怎样才能解决这个问题？