合并班级成员

给定这样的类结构:

class A:
    dependencies = ["x", "y"]

class B(A):
    dependencies = ["z"]

class C(A):
    dependencies = ["n", "m"]

class D(C):
    dependencies = ["o"]

我想知道是否有可能编写一个函数(最好是生活在A类),这些函数沿着这些方向做了一些事情:

@classmethod
def get_all_dependencies(cls):
    return super().get_all_dependencies() + cls.dependencies

对于上述类,预期输出将是:

>>> A.get_all_dependencies():
["x", "y"]
>>> B.get_all_dependencies():
["x", "y", "z"]
>>> C.get_all_dependencies():
["x", "y", "n", "m"]
>>> D.get_all_dependencies():
["x", "y", "n", "m", "o"]

显然上面的代码不起作用 - 它只返回dependencies我调用它的类.我不确定如何让它在所有类中递归工作？(我正在hasattr检查以确保父类调用get_all_dependencies().)

走了mro,抓住依赖是我要做的:

@classmethod
def get_dep(cls):
    return [d for c in cls.mro()[:-1] for d in getattr(c, 'dependencies')]

与cls.mro()[:-1]被用来排除object.

返回:

>>> A.get_dep()
['x', 'y']
>>> B.get_dep()
['z', 'x', 'y']
>>> C.get_dep()
['n', 'm', 'x', 'y']
>>> D.get_dep()
['o', 'n', 'm', 'x', 'y']