code: def sid(self):
      # for backwards compatibility
      return self.asset
  
imports: from warnings import warn
  import pandas
  from catalyst.assets import Asset, Future
  from catalyst.utils.input_validation import expect_types
  from .utils.enum import enum
  from catalyst._protocol import BarData
label_desc: Use image node_id 2 for calling the Position obj's underlying member method code with example usage: obj.sid() and returns: self