WT 6-3: Reuse DataWeave code using modules Error

Hi can anyone advise on what the issue is I'm getting when doing this walkthough?

Dataweave is

%dw 2.0

import dw::core::Strings

import modules::Util

output application/xml

var remapObject = {

Label: {key: (k,v) -> upper(k), value: ((k,v) -> Strings::capitalize(v)) }

}

---

//vars.transactions[0].customerRef

//vars.accounts[vars.transactions[0].customerRef as String]

do {

var joinData =

{transactions:

vars.transactions mapObject((value,key,index) ->

log("\n\nNext step $(index), key is $(key), and the customerRef is $(value.customerRef as String) \n", {}) ++

{ (Strings::dasherize(key ++ "Number" ++ index)): (value ++

vars.accounts[value.customerRef as String] as Object)

}

)

}

---

Util::pascalize(joinData) modules::APDevDataWeave::remap remapObject

}

And I get errors in dataweave stating

Unable to resolve reference of Strings::trim.

Unable to resolve reference of Strings::upper.

Unable to resolve reference of Strings::upper.

Unable to resolve reference of Strings::upper.

I get the same if I import the solution as well.

This is from the mule443 course.