# Breakpoint 3, socket_getaddrinfo (self=self@entry=0xb705c034, args=args@entry=0xb71650c4, 
#     kwargs=kwargs@entry=0x0) at /home/p/cpython-tip/Modules/socketmodule.c:5487
# 5487  {
# ... 
# 5513          idna = _PyObject_CallMethodId(hobj, &PyId_encode, "s", "idna");
# (gdb) 
# 5514          if (!idna)
# (gdb) print *idna
# $3 = {_ob_next = 0xb7241934, _ob_prev = 0xb70c86b8, ob_refcnt = 2, 
#   ob_type = 0x82d1ac0 <PyLong_Type>}
# (gdb) n
# 5516          assert(PyBytes_Check(idna));
# (gdb) 
# 
# Program received signal SIGABRT, Aborted.
# 0xb77a6d4c in __kernel_vsyscall ()
# 
# "host" argument can be set to a subclass of unicode with a custom "encode" 
# method. "encode" returns unexpected type. assert is not compiled in release
# mode, so this will lead to a type confusion later on.

import socket as so

class H(type("s")):
  def encode(self, x):
    return 666

h = H()
so.getaddrinfo(host=h, port=1337)