code: def resize_volume(self, volumeObj, sizeInGb, bsize=1000):
          
          current_vol = self.get_volume_by_id(volumeObj.id)
          if current_vol.size_kb > (sizeInGb * bsize * bsize):
              raise RuntimeError(
                  "resize_volume() - New size needs to be bigger than: %d KBs" % current_vol.size_kb)
          
          resizeDict = { 'sizeInGB' : str(sizeInGb) }
          response = self.conn.connection._do_post("{}/{}{}/{}".format(
              self.conn.connection._api_url, "instances/Volume::", volumeObj.id, 'action/setVolumeSize'), json=resizeDict)
          return response
docs: Resize a volume to new GB size, must be larger than original.
          :param volumeObj: ScaleIO Volume Object
          :param sizeInGb: New size in GB (have to be larger than original)
          :param bsize: 1000
          :return: POST request response
          :rtype: Requests POST response object