Power bi report builder error

when i am using custom code 

for localizing Data 

Public Function GetLocalizedValue(name as String, culture as String) as String
Try
Return PDSReports.LocalizedValue.GetString(TRIM(name), TRIM(culture) )
Catch ex As Exception
Return ex.Message
End Try
End Function

i got error like-

There is an error on line 2 of custom code: [BC30451] 'PDSReports' is not declared. It may be inaccessible due to its protection level.

i tried so many solutions ... guide me if you know some reference about it...thanks in advance  ...#powerbireportbuilder