dear all , i got this error when try to close POS sessions any advice

Traceback (most recent call last):
  File "/opt/odoo/openerp/http.py", line 544, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/opt/odoo/openerp/http.py", line 581, in dispatch
    result = self._call_function(**self.params)
  File "/opt/odoo/openerp/http.py", line 317, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/opt/odoo/openerp/service/model.py", line 118, in wrapper
    return f(dbname, *args, **kwargs)
  File "/opt/odoo/openerp/http.py", line 314, in checked_call
    return self.endpoint(*a, **kw)
  File "/opt/odoo/openerp/http.py", line 810, in __call__
    return self.method(*args, **kw)
  File "/opt/odoo/openerp/http.py", line 410, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo/addons/web/controllers/main.py", line 944, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/opt/odoo/addons/web/controllers/main.py", line 936, in _call_kw
    return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs)
  File "/opt/odoo/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/opt/odoo/openerp/models.py", line 1549, in fields_view_get
    xarch, xfields = View.postprocess_and_fields(cr, uid, self._name, etree.fromstring(result['arch']), view_id, context=ctx)
  File "/opt/odoo/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/opt/odoo/openerp/addons/base/ir/ir_ui_view.py", line 839, in postprocess_and_fields
    self.raise_view_error(cr, user, message, view_id, context)
  File "/opt/odoo/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/opt/odoo/openerp/addons/base/ir/ir_ui_view.py", line 362, in raise_view_error
    raise AttributeError(message)
AttributeError: Field `nro_facturas` does not exist

Error context:
View `pos.session.form.view`
[view_id: 798, xml_id: point_of_sale.view_pos_session_form, model: pos.session, parent_id: n/a]