PyObject_New not running tp_new for iterators?

[Gregory Bond]

I'm trying to extend Python with an iterator class that should be 
returned from a factory function.

For some reason the iterator object is not being properly initialised if 
the iterator is created in a C function.  It works just fine if the 
object is created using the class contructor

Trying to minimise the cut-n-paste, but:
typedef struct {
    PyObject_HEAD
      int i;
      
} MyIter;

static PyObject *
MyIter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    MyIter *self;
    self = (MyIter *)type->tp_alloc(type, 0);
    if (self) {
       self->i = 0;
    }
    return (PyObject *)self;
}
static PyObject *
MyIter_Iter(PyObject *self)
{
   Py_INCREF(self);
   return self;
}
static PyObject *
MyIter_Next(PyObject *self)
{
   MyIter *ep = (MyIter *) self;
   return Py_BuildValue("i", ep->i++);
}

plus the usual type stucture.  This simple iterator returns the integers 
from 0 to (programmer's) infinity.

This works fine if I create the object directly:
Python 2.3.1 (#3, Oct  1 2003, 16:18:11) 
[GCC 3.3] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
import myiter
e = myiter.MyIter()
str(e)
'<myiter.MyIter object at 0x184050>'
e.next()
0
e.next()
1
e.next()
2
e.next()
3
However, if I create the MyIter object from a C factory function:
static PyObject *
FromFile(PyObject *self, PyObject *args)
{
   MyIter *ro;
   
   if (!PyArg_ParseTuple(args, ""))
        return NULL;

   if (!(ro = PyObject_New(MyIter, &MyIterType)))
      return NULL;
   return (PyObject *)ro;
}
static PyMethodDef My_methods[] = {
   {"FromFile",  FromFile, METH_VARARGS,
    "Return an  iterator."},
    {NULL}  /* Sentinel */
};
then the MyIter object is not properly initialised!
f = myiter.FromFile()
f
<myiter.MyIter object at 0x184070>
f.next()
-2080374694
f.next()
-2080374693
f.next()
-2080374692

I tried a similar problem with a plane-old-object using tp_members 
(rather than an iterator object) and that worked fine, even from a 
factory function.

I've looked long and hard at the API doc, but I'm stumped.....  I've 
checked a couple of examples and they just do what I'm doing!

What am I missing?
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