Hum, _PyType_CheckConsistency() fails on the following assertion during Python finalization:

    ASSERT(type->tp_mro != NULL && PyTuple_Check(type->tp_mro));

Error:
---
/home/vstinner/prog/python/master/python: No module named asyncio.__main__; 'asyncio' is a package and cannot be directly executed
Objects/typeobject.c:149: _PyType_CheckConsistency: Assertion "(type->tp_mro != ((void *)0) && ((((((PyObject*)(type->tp_mro))->ob_type))->tp_flags & ((1UL << 26))) != 0))" failed
Enable tracemalloc to get the memory block allocation traceback

object  : <enum 'AddressFamily'>
type    : EnumMeta
refcount: 1
address : 0x9138f0
Fatal Python error: _PyObject_AssertFailed

Current thread 0x00007ffff7be8740 (most recent call first):
---

gdb traceback:
---
(gdb) where
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007ffff7c0f895 in __GI_abort () at abort.c:79
#2  0x000000000055bf91 in fatal_error (prefix=0x0, msg=0x68a47d "_PyObject_AssertFailed", status=-1) at Python/pylifecycle.c:2088
#3  0x000000000055bfbd in Py_FatalError (msg=0x68a47d "_PyObject_AssertFailed") at Python/pylifecycle.c:2098
#4  0x000000000047be0f in _PyObject_AssertFailed (obj=<EnumMeta() at remote 0x9138f0>, 
    expr=0x68d720 "(type->tp_mro != ((void *)0) && ((((((PyObject*)(type->tp_mro))->ob_type))->tp_flags & ((1UL << 26))) != 0))", msg=0x0, 
    file=0x68d632 "Objects/typeobject.c", line=149, function=0x690ba0 <__func__.14343> "_PyType_CheckConsistency") at Objects/object.c:2197
#5  0x000000000048ebd8 in _PyType_CheckConsistency (type=0x9138f0) at Objects/typeobject.c:149
#6  0x00000000004770a5 in _PyObject_CheckConsistency (op=<AddressFamily at remote 0x7fffea7a0870>) at Objects/object.c:35
#7  0x000000000058de3c in gc_check_object (gc=0x7fffea7a0860) at Modules/gcmodule.c:1280
#8  0x000000000058de90 in _PyGC_CheckAllObjets () at Modules/gcmodule.c:1290
#9  0x000000000058f4a0 in gc_check_object_debugger () at Modules/gcmodule.c:2007
#10 0x000000000058f7c7 in PyObject_GC_Del (op=0x7fffea7a27c0) at Modules/gcmodule.c:2109
#11 0x0000000000467188 in dict_dealloc (mp=0x7fffea7a27c0) at Objects/dictobject.c:1996
#12 0x000000000047be44 in _Py_Dealloc (op={}) at Objects/object.c:2212
#13 0x0000000000461cce in _Py_DECREF (filename=0x6855a0 "./Include/object.h", lineno=533, op={}) at ./Include/object.h:470
#14 0x0000000000461d1c in _Py_XDECREF (op={}) at ./Include/object.h:533
#15 0x0000000000462fef in free_keys_object (keys=0x9120e0) at Objects/dictobject.c:580
#16 0x000000000046284f in dictkeys_decref (dk=0x9120e0) at Objects/dictobject.c:324
#17 0x00000000004664f2 in PyDict_Clear (op={}) at Objects/dictobject.c:1722
#18 0x00000000004969b8 in type_clear (type=0x911c50) at Objects/typeobject.c:3637
#19 0x0000000000490d03 in subtype_clear (self=<EnumMeta() at remote 0x911c50>) at Objects/typeobject.c:1118
#20 0x000000000058d390 in delete_garbage (collectable=0x7fffffffcef0, old=0x7d2560 <_PyRuntime+416>) at Modules/gcmodule.c:931
#21 0x000000000058d833 in collect (generation=2, n_collected=0x0, n_uncollectable=0x0, nofail=1) at Modules/gcmodule.c:1100
#22 0x000000000058f175 in _PyGC_CollectNoFail () at Modules/gcmodule.c:1915
#23 0x000000000054759c in PyImport_Cleanup () at Python/import.c:589
#24 0x000000000055a442 in Py_FinalizeEx () at Python/pylifecycle.c:1162
#25 0x000000000055c1e5 in Py_Exit (sts=1) at Python/pylifecycle.c:2188
#26 0x00000000005677fb in handle_system_exit () at Python/pythonrun.c:642
#27 0x0000000000567821 in PyErr_PrintEx (set_sys_last_vars=1) at Python/pythonrun.c:652
#28 0x00000000005674c5 in PyErr_Print () at Python/pythonrun.c:548
#29 0x00000000004222f2 in pymain_run_module (modname=0x7db6d0 L"asyncio", set_argv0=1) at Modules/main.c:566
#30 0x0000000000422ad6 in pymain_run_python (interp=0x7da350, exitcode=0x7fffffffd254) at Modules/main.c:799
#31 0x0000000000422c6a in pymain_main (args=0x7fffffffd2a0) at Modules/main.c:877
#32 0x0000000000422d4e in _Py_UnixMain (argc=3, argv=0x7fffffffd3c8) at Modules/main.c:922
#33 0x0000000000420796 in main (argc=3, argv=0x7fffffffd3c8) at ./Programs/python.c:16
---

Maybe my assumption on tp_mro was wrong. I will remove the assertion.