diff --git a/python/libvirt-override-api.xml b/python/libvirt-override-api.xml
index 07e4a78a1d5ceec7e8c38d2472ce70fe5357f191..704fee90b3b6e8d27e0ab4ba023f8f64a3a01f98 100644
--- a/python/libvirt-override-api.xml
+++ b/python/libvirt-override-api.xml
@@ -401,9 +401,8 @@
       <info>Get the I/O tunables for a block device</info>
       <arg name='dom' type='virDomainPtr' info='pointer to the domain'/>
       <arg name='disk' type='const char *' info='disk name'/>
-      <arg name='params' type='virTypedParameterPtr' info='Pointer to blkio tuning params object'/>
       <arg name='flags' type='unsigned int' info='an OR&apos;ed set of virDomainModificationImpact'/>
-      <return type='int' info='0 in case of success, -1 in case of failure'/>
+      <return type='virTypedParameterPtr' info='the I/O tunables value or None in case of error'/>
     </function>
     <function name='virDomainBlockPeek' file='python'>
       <info>Read the contents of domain's disk device</info>
diff --git a/python/libvirt-override.c b/python/libvirt-override.c
index 8a643a30bd2fc027b79b15367b6d5bdbacf89c7f..a704e78240d5e8e68e041042cb2bb73e246d7238 100644
--- a/python/libvirt-override.c
+++ b/python/libvirt-override.c
@@ -3301,7 +3301,7 @@ libvirt_virDomainSetBlockIoTune(PyObject *self ATTRIBUTE_UNUSED,
     int nparams = 0, i;
     int c_ret;
 
-    if (!PyArg_ParseTuple(args, (char *)"Ozi:virDomainSetBlockIoTune",
+    if (!PyArg_ParseTuple(args, (char *)"OzOi:virDomainSetBlockIoTune",
                           &pyobj_domain, &disk, &pyinfo, &flags))
         return(NULL);
     domain = (virDomainPtr) PyvirDomain_Get(pyobj_domain);
@@ -3395,7 +3395,7 @@ libvirt_virDomainGetBlockIoTune(PyObject *self ATTRIBUTE_UNUSED,
     virTypedParameterPtr params;
     int c_ret;
 
-    if (!PyArg_ParseTuple(args, (char *)"Oi:virDomainGetBlockIoTune",
+    if (!PyArg_ParseTuple(args, (char *)"Ozi:virDomainGetBlockIoTune",
                           &pyobj_domain, &disk, &flags))
         return(NULL);
     domain = (virDomainPtr) PyvirDomain_Get(pyobj_domain);