Are classobjects singletons?

Question

If we have x = type(a) and x == y, does it necessarily imply that x is y?

Here is a counter-example, but it\'s a cheat:

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Answer 1

I'm not aware of any documentation about how == works for types, but it definitely works by identity. You can see that the CPython 2.7 implementation is a pointer comparison:

static PyObject*
type_richcompare(PyObject *v, PyObject *w, int op)
{
    ...

    /* Compare addresses */
    vv = (Py_uintptr_t)v;
    ww = (Py_uintptr_t)w;
    switch (op) {
    ...
    case Py_EQ: c = vv == ww; break;

In CPython 3.5, type doesn't implement its own tp_richcompare, so it inherits the default equality comparison from object, which is a pointer comparison:

PyTypeObject PyType_Type = {
    ...
    0,                                          /* tp_richcompare */