code: def op_extract(op_name, data, senders, inputs, outputs, block_id, vtxindex, txid):
      
      global EXTRACT_METHODS
  
      if op_name not in EXTRACT_METHODS.keys():
          raise Exception("No such operation '%s'" % op_name)
  
      method = EXTRACT_METHODS[op_name]
      op_data = method( data, senders, inputs, outputs, block_id, vtxindex, txid )
      return op_data
docs: Extract an operation from transaction data.
      Return the extracted fields as a dict.