Currently my search view looks something like this:

<record id="view_email_scheduled_search" model="ir.ui.view">
  <field name="name">sale.order_email.scheduled_email.search</field>
  <field name="model">sale.order_email.scheduled_email</field>
  <field name="arch" type="xml">
    <search string="Templates">
      <field name="name"/>
      <field name="subject"/>
      <field name="order_id"/>
      <field name="order_line_id"/>
    </search>
  </field>
</record>

Is it possible to add a search option that I can do with code?