Executing procedures with multiple arguments

Hi,
I have two modules:

Module 2 - where i've defined

Public Sub Workbook_Open(v_fileName As String, MyDir As String)
.....
end

Module 1 - where I will call the procedure defined in Module 2

Sub DirLoop()

      Dim MyFile As String, Sep As String

     MyDir = InputBox(Prompt:="Enter folder path", _
          Title:="Folder Path", Default:="")
          
      If Sep = "\" Then
         ' Windows platform search syntax.
          MyFile = Dir(MyDir & Sep & "*.xlsx")
      End If

      Do While MyFile <> ""

          Workbook_Open(MyDir & Sep & MyFile, MyDir)
          MyFile = Dir()
                 
      Loop

End Sub

but when executing the module 1 I have a syntax error message. What I'm doing wrong?
Thank You