BytesIO.getvalue() and StringIO.getvalue() are METH_NOARGS.

Modules/_io/bytesio.c

@@ -818,7 +818,7 @@ static struct PyMethodDef bytesio_methods[] = {
     {"readline",   (PyCFunction)bytesio_readline,   METH_VARARGS, readline_doc},
     {"readlines",  (PyCFunction)bytesio_readlines,  METH_VARARGS, readlines_doc},
     {"read",       (PyCFunction)bytesio_read,       METH_VARARGS, read_doc},
-    {"getvalue",   (PyCFunction)bytesio_getvalue,   METH_VARARGS, getval_doc},
+    {"getvalue",   (PyCFunction)bytesio_getvalue,   METH_NOARGS,  getval_doc},
     {"seek",       (PyCFunction)bytesio_seek,       METH_VARARGS, seek_doc},
     {"truncate",   (PyCFunction)bytesio_truncate,   METH_VARARGS, truncate_doc},
     {"__getstate__",  (PyCFunction)bytesio_getstate,  METH_NOARGS, NULL},

Modules/_io/stringio.c

@@ -827,7 +827,7 @@ stringio_newlines(stringio *self, void *context)
 
 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},