docs: def volume_create(name, size=100, snapshot=None, voltype=None, **kwargs):
      '''
      Create block storage device
      '''
      conn = get_conn()
      create_kwargs = {'name': name,
                       'size': size,
                       'snapshot': snapshot,
                       'voltype': voltype}
      create_kwargs['availability_zone'] = kwargs.get('availability_zone', None)
      return conn.volume_create(**create_kwargs)