code: func (as *accountSet) containsTx(tx *types.Transaction) bool {
  	if addr, err := types.Sender(as.signer, tx); err == nil {
  		return as.contains(addr)
  	}
  	return false
  }
docs: // containsTx checks if the sender of a given tx is within the set. If the sender
  // cannot be derived, this method returns false.