code: func (view *UtxoViewpoint) fetchUtxosMain(db database.DB, outpoints map[wire.OutPoint]struct{}) error {
  	// Nothing to do if there are no requested outputs.
  	if len(outpoints) == 0 {
  		return nil
  	}
  
  	// Load the requested set of unspent transaction outputs from the point
  	// of view of the end of the main chain.
  	//
  	// NOTE: Missing entries are not considered an error here and instead
  	// will result in nil entries in the view.  This is intentionally done
  	// so other code can use the presence of an entry in the store as a way
  	// to unnecessarily avoid attempting to reload it from the database.
  	return db.View(func(dbTx database.Tx) error {
  		for outpoint := range outpoints {
  			entry, err := dbFetchUtxoEntry(dbTx, outpoint)
  			if err != nil {
  				return err
  			}
  
  			view.entries[outpoint] = entry
  		}
  
  		return nil
  	})
  }
docs: // fetchUtxosMain fetches unspent transaction output data about the provided
  // set of outpoints from the point of view of the end of the main chain at the
  // time of the call.
  //
  // Upon completion of this function, the view will contain an entry for each
  // requested outpoint.  Spent outputs, or those which otherwise don't exist,
  // will result in a nil entry in the view.