Is it legal VB to return a collection as a property from a class?

[cappy2112]

I've created a collection in a class, now want to return it via a property in the class.

The invocation (below) to return the class is giving me "Compile Error Argument not optional"

There are no arguments- why is the compiler complaining?

Sub CreateLabReport()

Dim filereader As New clsReadTextFile
Dim AllTestNames As New Collection
 
    AllTestNames = filereader.getAllTestNames() ' this line causes error msg

end sub

The AllTestNames collection is defined in another class as follows

Private colAlltests As New Collection
Property Get getAllTestNames() As Collection
    getAllTestNames = colAlltests
End Property

Private Sub Class_Initialize()
    testNamesMasterList = "testnames.txt"
    Call ReadTestNames
End Sub

Private Sub SeparateTestnames(listofTests As String)

Dim newtest As clsTestDescription
Dim teststr() As String
Dim x, lastTestNum As Integer
Dim testNumber As Long

    teststr() = Split(listofTests, vbCrLf)
    lastTestNum = UBound(teststr)
    testNumber = 1 ' these are arbitrary test numbers
    For x = 0 To lastTestNum
        'If teststr(x) <> "" Then
        If LenB(teststr(x)) <> 0 Then ' don't add to collection, if string is empty
            Set newtest = New clsTestDescription
            newtest.letTestname = Trim(teststr(x))
            newtest.letTestNumber = testNumber    ' arbitrary test number
            colAlltests.Add newtest
            testNumber = testNumber + 1
        End If
    Next x
End Sub