From Guido van Rossum:
It works the same way as
.extend()
except that it also returnsself
. I
can’t find docs explaining this. 🙁
Here is the relevant source code taken from listobject.c
:
list_inplace_concat(PyListObject *self, PyObject *other)
{
PyObject *result;
result = listextend(self, other);
if (result == NULL)
return result;
Py_DECREF(result);
Py_INCREF(self);
return (PyObject *)self;
}
I’ve raised a bug report to have the documentation fixed: http://bugs.python.org/issue16701