BytesIO.getvalue() and StringIO.getvalue() are METH_NOARGS.
diff --git a/Modules/_io/stringio.c b/Modules/_io/stringio.c
index 13e3b58..5bb80cb 100644
--- a/Modules/_io/stringio.c
+++ b/Modules/_io/stringio.c
@@ -827,7 +827,7 @@
static struct PyMethodDef stringio_methods[] = {
{"close", (PyCFunction)stringio_close, METH_NOARGS, stringio_close_doc},
- {"getvalue", (PyCFunction)stringio_getvalue, METH_VARARGS, stringio_getvalue_doc},
+ {"getvalue", (PyCFunction)stringio_getvalue, METH_NOARGS, stringio_getvalue_doc},
{"read", (PyCFunction)stringio_read, METH_VARARGS, stringio_read_doc},
{"readline", (PyCFunction)stringio_readline, METH_VARARGS, stringio_readline_doc},
{"tell", (PyCFunction)stringio_tell, METH_NOARGS, stringio_tell_doc},