code: func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Uint64, error) {
  	// Ask transaction pool for the nonce which includes pending transactions
  	if blockNr == rpc.PendingBlockNumber {
  		nonce, err := s.b.GetPoolNonce(ctx, address)
  		if err != nil {
  			return nil, err
  		}
  		return (*hexutil.Uint64)(&nonce), nil
  	}
  	// Resolve block number and use its state to ask for the nonce
  	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
  	if state == nil || err != nil {
  		return nil, err
  	}
  	nonce := state.GetNonce(address)
  	return (*hexutil.Uint64)(&nonce), state.Error()
  }
docs: // GetTransactionCount returns the number of transactions the given address has sent for the given block number