Python +；的操作数类型不受支持：'；类型'；和'；元组'；

我是新手。我喜欢这个python配方，但是当我尝试在django上运行时会出现错误

def get_noconflict_metaclass(bases, left_metas, right_metas):
    """Not intended to be used outside of this module, unless you know
    what you are doing."""
    # make tuple of needed metaclasses in specified priority order
    metas = left_metas + tuple(map(type, bases)) + right_metas
    needed_metas = remove_redundant(metas)

错误

以下是数值：

left_metas (<class 'ccad.admin.ModelAdminWithForeignKeyLinksMetaclass'>,)
right_metas ()
...
 File "/opt/myenv/myproject/ccad/admin.py", line 201, in 
class SOAdetailAdmin(admin.ModelAdmin):
 File "/opt/myenv/myproject/ccad/noconflict.py", line 52, in make_class
def make_class(name, bases, adict):
 File "/opt/myenv/myproject/ccad/noconflict.py", line 30, in get_noconflict_metaclass
metas = left_metas + tuple(map(type(), bases,),) + right_metas
TypeError: Error when calling the metaclass bases
unsupported operand type(s) for +: 'type' and 'tuple'

---

谢谢你的评论。这确实有助于指出我应该做什么

根据代码段作者的解释和示例： 这里的问题是，因为D继承自A，所以它的元类必须继承自M_A，而不能是M_B

classmaker通过自动从M_A和M_B继承来解决此问题：

>>> class D(A):
...     __metaclass__=classmaker(right_metas=(M_B,))
>>> type(D)

我将原始代码更改为此，django工作正常：

class SOAdetailAdmin(admin.ModelAdmin):
    __metaclass__ = classmaker(right_metas=(ModelAdminWithForeignKeyLinksMetaclass,))

---

left_-metas

和

right_-metas

的值是什么？在添加它们之前，您可以打印left_-metas和right_-metas吗？@Charlesliasm请为这个问题“新手”提供您的输入参数？？使用元类？是的，我第一次接触元类。我通常在django中使用meta

>>> class D(A):
...     __metaclass__=classmaker(right_metas=(M_B,))
>>> type(D)

class SOAdetailAdmin(admin.ModelAdmin):
    __metaclass__ = classmaker(right_metas=(ModelAdminWithForeignKeyLinksMetaclass,))