fix interface implements

RQL/Repository/Repository.vb

@@ -145,14 +145,14 @@ Namespace Linq
         Public Shared ReadOnly Property DefaultFile As String =
             App.ProductSharedDIR & "/RQL.Provider.json"
 
-        Private Function ISaveHandle_Save(Optional Path As String = "", Optional encoding As Encoding = Nothing) As Boolean Implements ISaveHandle.Save
+        Private Function ISaveHandle_Save(Path As String, encoding As Encoding) As Boolean Implements ISaveHandle.Save
             If String.IsNullOrEmpty(Path) Then
                 Path = DefaultFile
             End If
             Return Me.GetJson.SaveTo(Path, encoding)
         End Function
 
-        Public Function Save(Optional Path As String = "", Optional encoding As Encodings = Encodings.UTF8) As Boolean Implements ISaveHandle.Save
+        Public Function Save(Path As String, Optional encoding As Encodings = Encodings.UTF8) As Boolean Implements ISaveHandle.Save
             Return ISaveHandle_Save(Path, encoding.CodePage)
         End Function
     End Class