[libvirt] Python setBlkioParameters function broken

I've tried to use domain.setBlkioParameters with ipython, and I'm finding it's throwing the mysterious error: ubuntu@host-192-168-0-7:~$ dpkg -l | grep libvirt ii libvirt-bin 1.2.2-0ubuntu13.1 amd64 programs for the libvirt library ii libvirt0 1.2.2-0ubuntu13.1 amd64 library for interfacing with different virtualization systems ii python-libvirt 1.2.2-0ubuntu1 amd64 libvirt Python bindings ubuntu@host-192-168-0-7:~$ sudo ipython ...... In [85]: doms[0] Out[85]: <libvirt.virDomain at 0x7fe688879250> In [86]: params Out[86]: {'weight': 250} In [87]: doms[0].setBlkioParameters(params, 0) libvirt: error : argument unsupported: parameter '' not supported --------------------------------------------------------------------------- libvirtError Traceback (most recent call last) <ipython-input-87-026c35502a5c> in <module>() ----> 1 doms[0].setBlkioParameters(params, 0) /usr/lib/python2.7/dist-packages/libvirt.pyc in setBlkioParameters(self, params, flags) 1961 """Change the blkio tunables """ 1962 ret = libvirtmod.virDomainSetBlkioParameters(self._o, params, flags) -> 1963 if ret == -1: raise libvirtError ('virDomainSetBlkioParameters() failed', dom=self) 1964 return ret 1965 libvirtError: argument unsupported: parameter '' not supported The libvirt debug log info are as following: 2014-05-27 08:37:27.752+0000: 7559: debug : remoteDispatchDomainSetBlkioParametersHelper:7328 : server=0x7fd81deec930 client=0x7fd81df05170 msg=0x7fd81df06eb0 rerr=0x7fd816059c80 args=0x7fd7e40009a0 ret=0x7fd7e4000910 2014-05-27 08:37:27.752+0000: 7559: debug : virObjectNew:199 : OBJECT_NEW: obj=0x7fd7e4000c60 classname=virDomain 2014-05-27 08:37:27.752+0000: 7559: debug : virObjectRef:293 : OBJECT_REF: obj=0x7fd7f80011f0 2014-05-27 08:37:27.752+0000: 7559: debug : virDomainSetBlkioParameters:3985 : dom=0x7fd7e4000c60, (VM: name=instance-00000050, uuid=f844cf42-07d1-4b73-8de7-7437bf32aab0), params=0x7fd7e4000930, nparams=1, flags=0 2014-05-27 08:37:27.752+0000: 7559: debug : virDomainSetBlkioParameters:3986 : params[""]=(uint)250 2014-05-27 08:37:27.752+0000: 7559: debug : virObjectRef:293 : OBJECT_REF: obj=0x7fd81deec300 2014-05-27 08:37:27.752+0000: 7559: debug : virAccessManagerCheckConnect:215 : manager=0x7fd81deec300(name=stack) driver=QEMU perm=0 2014-05-27 08:37:27.752+0000: 7559: debug : virAccessManagerCheckConnect:215 : manager=0x7fd81deec370(name=none) driver=QEMU perm=0 2014-05-27 08:37:27.752+0000: 7559: debug : virObjectUnref:256 : OBJECT_UNREF: obj=0x7fd81deec300 2014-05-27 08:37:27.752+0000: 7559: error : virTypedParamsValidate:97 : argument unsupported: parameter '' not supported -- ------------ Jackie Best Regards