docs: def _gen_vol_xml(vmname,
                   diskname,
                   disktype,
                   size,
                   pool):
      '''
      Generate the XML string to define a libvirt storage volume
      '''
      size = int(size) * 1024  # MB
      context = {
          'name': vmname,
          'filename': '{0}.{1}'.format(diskname, disktype),
          'volname': diskname,
          'disktype': disktype,
          'size': six.text_type(size),
          'pool': pool,
      }
      fn_ = 'libvirt_volume.jinja'
      try:
          template = JINJA.get_template(fn_)
      except jinja2.exceptions.TemplateNotFound:
          log.error('Could not load template %s', fn_)
          return ''
      return template.render(**context)