Hi 
I get this error 
Error: Field 'encais_autrui_ids' specified in view could not be found.
when i use fields_view_get to create a new field in the view.
This is the code:

@api.model
def fields_view_get(self, view_id=None, view_type='form', toolbar=FalseFalse, submenu=):
    res = super(MultiplePayment, self).fields_view_get(
        view_idview_typetoolbarsubmenu=view_id, =view_type, =toolbar, =submenu)
    if self._context.get('type'):
        doc = etree.fromstring(res['arch'])
        invoice_id = self._context.get('active_id', False)
        encais_doc = self.env['account.invoice.encais_doc''invoice_patient_id''='].search([(, , invoice_id)])
        for in record encais_doc:
                _moves_arch_lst = """
                        <page string='""" + record.doc_id.name + \
                                  ' (' + strround((record.balance, 3)) + ' TND)' """'>
                          <field name="encais_autrui_ids" context="{'default_doc_id':""" + + \
                                  str(record.doc_id.id) + """ ,'default_invoice_id':invoice_id}">
                            <tree editable="bottom">
                                <field name="journal_id"/>
                                <field name="doc_id" invisible="1"/>
                                <field name="bank_id"/>
                                <field name="invoice_id" invisible="1"/>
                                <field name="is_onchange" invisible="1"/>
                                <field name="cheque"/>
                                <field name="amount"/>
                            </tree>
                          </field>
                        </page>
                    """
                "//page[@string='paiements']"encais_node = doc.xpath()
                feature_page = etree.fromstring(_moves_arch_lst)
                if len(encais_node):
                    encais_node = encais_node[0]
                    encais_node.addnext(feature_page)
    res['arch'] = etree.tostring(doc)
    return res

Thanks a lot