假设您有一个包含foo以下内容的包__init__.py：
from bar import *
作为bar任何安装了pip install bar.
现在，当您可以导入时，什么总是有效的bar：
from bar import submodule #works
import bar.submodule #works, too
现在我会假设以下事情都可以正常工作：
from foo import submodule # a) is possible
import foo.submodule # b) not possible ("no module named submodule")
from foo.bar import submodule # c) also impossible ("no module named submodule")
为什么他们不可能？从维护者的角度来看，我需要做什么才能使它们成为可能foo？
submodule并且bar是foo模块对象的成员，而不是它的子模块。因此，它们的行为与 的任何其他成员属性一样foo。您可以使用表单将它们带入第三个模块的模块命名空间from foo import ...，但不能直接import将它们相对于foo. 我想如果你sys.modules手动将它们入侵到所需的名称下你可以，但你真的不应该做这样的事情......
为了说明问题：
foo.py
# x and y are values in the foo namespace, available as member attributes
# of the foo module object when foo is imported elsewhere
x = 'x'
y = 'y'
bar.py
# the foo module object is added as a member attribute of bar on import
# with the name foo in the bar namespace
import foo
# the same foo object is aliased within the bar namespace with the name
# fooy
import foo as fooy
# foo.x and foo.y are referenced from the bar namespace as x and y,
# available as member attributes of the bar module object
from foo import x, y
# z is a member attribute of the bar module object
z = 'z'
baz.py
# brings a reference to the x, y, and z attributes of bar (x and y
# come in turn from foo, though that's not relevant to the import;
# it just cares that bar has x, y, and z attributes), in to the
# namespace of baz
from bar import x, y, z
# won't work, because foo is a member of bar, not a submodule
import bar.foo
# will work, for the same reason that importing x, y, and z work
from bar import foo