Hi,

I have problem with Odoo 12 theme tutorial, when i code "layout.xml"

<!-- Customize header  -->
<template id="custom_header" inherit_id="website.layout" name="Custom Header">

  <!-- Assign an id  -->
  <xpath expr="//div[@id='wrapwrap']/header" position="attributes">
    <attribute name="id">my_header</attribute>
  </xpath>

  <!-- Add an element after the top menu  -->
  <xpath expr="//div[@id='wrapwrap']/header/div" position="after">
    <div class="container">
      <div class="alert alert-info mt16" role="alert">
        <strong>Welcome</strong> in our website!
      </div>
    </div>
  </xpath>
</template>

running display error

Element '<xpath expr="//div[@id='wrapwrap']/header/div">' cannot be located in parent view
Error context:
View `Custom Header`
[view_id: 522, xml_id: n/a, model: n/a, parent_id: 380]
None" while parsing None:4, near
<data inherit_id="website.layout" name="Custom Header">
  <!-- Assign an id  -->
  <xpath expr="//div[@id='wrapwrap']/header" position="attributes">
    <attribute name="id">my_header</attribute>
  </xpath>
  <!-- Add an element after the top menu  -->
  <xpath expr="//div[@id='wrapwrap']/header/div" position="after">
    <div class="container">
      <div class="alert alert-info mt16" role="alert">
        <strong>Welcome</strong> in our website!
      </div>
    </div>
  </xpath>
</data>