python Package如何设置文件入口

someDir/
    main.py
    subModules/
        __init__.py
        subA.py
        subSubModules/
            __init__.py
            subSubA.py
 
# subA.py
 
def subAFun():
    print('Hello from subAFun')
 
def subAFunTwo():
    print('Hello from subAFunTwo')
 
# subSubA.py
 
def subSubAFun():
    print('Hello from subSubAFun')
 
def subSubAFunTwo():
    print('Hello from subSubAFunTwo')
 
# __init__.py from subDir
 
# Adds 'subAFun()' and 'subAFunTwo()' to the 'subDir' namespace
from .subA import *
 
# The following two import statement do the same thing, they add 'subSubAFun()' and 'subSubAFunTwo()' to the 'subDir' namespace. The first one assumes '__init__.py' is empty in 'subSubDir', and the second one, assumes '__init__.py' in 'subSubDir' contains 'from .subSubA import *'.
 
# Assumes '__init__.py' is empty in 'subSubDir'
# Adds 'subSubAFun()' and 'subSubAFunTwo()' to the 'subDir' namespace
from .subSubDir.subSubA import *
 
# Assumes '__init__.py' in 'subSubDir' has 'from .subSubA import *'
# Adds 'subSubAFun()' and 'subSubAFunTwo()' to the 'subDir' namespace
from .subSubDir import *
# __init__.py from subSubDir
 
# Adds 'subSubAFun()' and 'subSubAFunTwo()' to the 'subSubDir' namespace
from .subSubA import *
 
# main.py
 
import subDir
 
subDir.subAFun() # Hello from subAFun
subDir.subAFunTwo() # Hello from subAFunTwo
subDir.subSubAFun() # Hello from subSubAFun
subDir.subSubAFunTwo() # Hello from subSubAFunTwo