code: func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
  	result, _, _, err := DoCall(ctx, s.b, args, blockNr, vm.Config{}, 5*time.Second, s.b.RPCGasCap())
  	return (hexutil.Bytes)(result), err
  }
docs: // Call executes the given transaction on the state for the given block number.
  // It doesn't make and changes in the state/blockchain and is useful to execute and retrieve values.