i am not able to access function written in rdlc code

i am not able to access function written in rdlc code

Hi, I'm writing this simple function in code section of rdlc
Public Function GetGender(ByVal val as String) As String
Dim retVal as String = ""
If(val = "1")
retVal = "Male"
Else If (val = "2")
retVal = "???"
Else If (val = "3")
retVal = "???"
Else
retVal = "???"
End If
Return retVal
End Function
but in expression I am not able to access it by this statement
=Code.GetGender(..) any help please if I'm missing something