docs: def make_sender_info( self, block_hash, txn, i, block_height ):
          """
          Make sender information bundle for a particular input of
          a nulldata transaction.
  
          We'll use it to go find the transaction output that
          funded the ith input of the given tx.
          """
  
          inp = txn['ins'][i]
          ret = {
              # to be filled in...
              'scriptPubKey': None,
              'addresses': None,
  
              # for matching the input and sender funded
              "txindex": txn['txindex'],
              "relindex": txn['relindex'],
              "output_index": inp['outpoint']['index'],
              "block_hash": block_hash,
              "relinput": i,
              "block_height": block_height,
          }
  
          return ret