use multiple class in wpf

here i use two different class like person and passwordboxassistant in xaml in one application...

so how how to use

<Window x:Class="ITA.AdminMaster"
        xmlns:local="clr-namespace:ITA"
        xmlns:PassHelper="clr-namespace:ITA"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="AdminMaster" Height="567" Width="917">
    <Window.Resources>
        <local:Person x:Key="person"/>
        <PassHelper:PasswordBoxAssistant x:Key="PBA"/>  //here error that PasswordBoxAssistant does not exist in name space "clr-namespace:ITA"

     </Window.Resources>

</Window>