Visual Basic.NET - Error en la llamada a una función (He corregido lo enviado)

Public Function MaximoReg() As DataTable

    Try

        Dim cmd As New MySqlCommand

        cn.Open()

        cmd = New MySqlCommand("reg_max_calles")

        cmd.CommandType = CommandType.StoredProcedure

       cmd.Parameters.Add("@max_value")

        cmd.Connection = cn

        Dim dt As New DataTable

        Dim da As New MySqlDataAdapter(cmd)

        da.Fill(dt)

        Return dt

    Catch ex As Exception

        MsgBox(ex.Message)

        Return Nothing

    Finally

        cn.Close()

    End Try

End Function