[BUG] Problem getting the client package

[LaraSchvartzman]

Describe the bug
When I type go get "github.com/CovenantSQL/CovenantSQL/client" and after that go get "github.com/CovenantSQL/CovenantSQL/cmd/cql" I get the same terminal prompt:
go/src/github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces/transaction_wrapper.go:169:20: decodeDriver.TryDecodeAsNil undefined (type codec.genHelperDecDriver has no field or method TryDecodeAsNil)
Afterwards, when importing either package I get the error:
../../go/src/github.com/CovenantSQL/CovenantSQL/blockproducer/interfaces/transaction_wrapper.go:169:20: decodeDriver.TryDecodeAsNil undefined (type codec.genHelperDecDriver has no field or method TryDecodeAsNil)
This happens for WriteArrayElem, ReadArrayElem and TryDecodeAsNil
How can I fix this? Thanks!

To Reproduce
Commands to reproduce the behavior:

1. In the terminal type go get "github.com/CovenantSQL/CovenantSQL/client"
2. You will get the first behaviour described
3. In any Go IDE execute a basic script importing the package, for example:
   package main

import (
"fmt"
"github.com/CovenantSQL/CovenantSQL/client"
)
func main() {
fmt.Println("Hello World")
}
4. You will get the error described