Android Question Compare Null does not work

    Dim VersionAvisadoVencida As Object

Sub Test2
 
    Dim Params As Map
    Params.Initialize
 
    Dim VersionAvisadoVencida As String
    VersionAvisadoVencida = Para(Params,"AvisoVencida")
    Log(VersionAvisadoVencida)
    If VersionAvisadoVencida = "" Then VersionAvisadoVencida = "123"
    Log(VersionAvisadoVencida)
 
End Sub

Sub Para(Map As Map,Key As String) As String
 
    If Map.Get(Key) = Null Then
        Return ""
    Else
        Return Map.Get(Key)
    End If
 
End Sub