# 创建目录代码
import os
os.makedirs('glance/api')
os.makedirs('glance/cmd')
os.makedirs('glance/db')
l = []
l.append(open('glance/__init__.py','w'))
l.append(open('glance/api/__init__.py','w'))
l.append(open('glance/api/policy.py','w'))
l.append(open('glance/api/versions.py','w'))
l.append(open('glance/cmd/__init__.py','w'))
l.append(open('glance/cmd/manage.py','w'))
l.append(open('glance/db/models.py','w'))
map(lambda f:f.close() ,l)

glance/                   #Top-level package├── __init__.py      #Initialize the glance package├── api                  #Subpackage for api│   ├── __init__.py│   ├── policy.py│   └── versions.py├── cmd                #Subpackage for cmd│   ├── __init__.py│   └── manage.py└── db                  #Subpackage for db├── __init__.py└── models.py

#文件内容#policy.py
def get():print('from policy.py')#versions.py
def create_resource(conf):print('from version.py: ',conf)#manage.py
def main():print('from manage.py')#models.py
def register_models(engine):print('from models.py: ',engine)

glance/                   ├── __init__.py      from glance import apifrom glance import cmdfrom glance import db├── api                  │   ├── __init__.py  from glance.api import policyfrom glance.api import versions│   ├── policy.py│   └── versions.py├── cmd                 from glance.cmd import manage│   ├── __init__.py│   └── manage.py└── db                   from glance.db import models├── __init__.py└── models.py

glance/                   ├── __init__.py      from . import api  #.表示当前目录from . import cmdfrom . import db├── api                  │   ├── __init__.py  from . import policyfrom . import versions│   ├── policy.py│   └── versions.py├── cmd              from . import manage│   ├── __init__.py│   └── manage.py    from ..api import policy   #..表示上一级目录，想再manage中使用policy中的方法就需要回到上一级glance目录往下找api包，从api导入policy└── db               from . import models├── __init__.py└── models.py

glance/                   ├── __init__.py     from .api import *from .cmd import *from .db import *
├── api                  │   ├── __init__.py   __all__ = ['policy','versions'] │   ├── policy.py│   └── versions.py├── cmd               __all__ = ['manage']    │   ├── __init__.py│   └── manage.py    └── db                __all__ = ['models']              ├── __init__.py└── models.pyimport glance
policy.get()import glance