title: Expected singleton: hr.employee(1, 2)
body: <p>Good Day! Everybody I have an error while loading the <code>kanban</code> view.  I inherit the <code>hr.employee</code> <code>Kanban</code> xml and just add a condition if a certain documents expired,  it will add a Expired Documents notification in <code>kanban</code> view, here is the xml code:</p>
  
  <pre class="lang-xml prettyprint-override"><code>    &lt;record model="ir.ui.view" id="hr_kanban_view_employees_recruitment_kanban"&gt;
          &lt;field name="name"&gt;HR - Employees Kanban Document Status&lt;/field&gt;
          &lt;field name="model"&gt;hr.employee&lt;/field&gt;
          &lt;field name="inherit_id" ref="hr.hr_kanban_view_employees"/&gt;
          &lt;field name="arch" type="xml"&gt;
              &lt;xpath expr="//templates" position="before"&gt;
                  &lt;field name="employee_id"/&gt;
                  &lt;field name="documents_status"/&gt;
              &lt;/xpath&gt;
              &lt;xpath expr="//div[@class='oe_employee_details']/ul/li[@id='last_login']" position="inside"&gt;
                  &lt;span t-if="record.documents_status.raw_value" style="font-size: 100%%"
                          t-att-class="record.documents_status.raw_value==true'oe_kanban_button oe_kanban_color_3'"&gt;
                      &lt;field name="employee_id" readonly = "1"/&gt;
                      Has Expired Documents
                  &lt;/span&gt;
              &lt;/xpath&gt;
          &lt;/field&gt;
      &lt;/record&gt;
  </code></pre>
  
  <p>and the model for <code>documents_status</code> field</p>
  
  <p>and when loading</p>
  
  <pre class="lang-python prettyprint-override"><code>documents_status = fields.Boolean('DocumentStatus', readonly = True,store = False,compute ='getdocumentStatus')
  
      @api.one
      def getdocumentStatus(self):
          raise Warning(self.employee_id)
          server_date = datetime.datetime.strptime(DATE_NOW.strftime("%Y-%m-%d") ,"%Y-%m-%d")
          result = {}
  
          for id in self.ids:
              result[id] = {
                  'documents_status': True
              }
              totaldoc = self.env['hr.employee_documents'].search_count([('date_expiry', '&lt;', server_date),('employee_doc_id','=', id)])
              if totaldoc &gt; 0:
                  result[id]['documents_status'] = True
                  self.documents_status = True
              else:
                  result[id]['documents_status'] = False
                  self.documents_status = False
          return result
  </code></pre>
  
  <p>the <code>kanban</code> view in employee an error occurred</p>
  
  <blockquote>
    <p>Expected singleton: hr.employee(1, 2). </p>
  </blockquote>
  
  <p>will someone help me with this and Thanks in Advance.</p>