Odoo Server Error
Traceback (most recent call last):
  File "/opt/odoo/odoo/http.py", line 642, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/opt/odoo/odoo/http.py", line 684, in dispatch
    result = self._call_function(**self.params)
  File "/opt/odoo/odoo/http.py", line 334, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/opt/odoo/odoo/service/model.py", line 101, in wrapper
    return f(dbname, *args, **kwargs)
  File "/opt/odoo/odoo/http.py", line 327, in checked_call
    result = self.endpoint(*a, **kw)
  File "/opt/odoo/odoo/http.py", line 942, in _call_
    return self.method(*args, **kw)
  File "/opt/odoo/odoo/http.py", line 507, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo/addons/web/controllers/main.py", line 892, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/opt/odoo/addons/web/controllers/main.py", line 884, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/opt/odoo/odoo/api.py", line 689, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "/opt/odoo/odoo/api.py", line 680, in call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/opt/odoo/odoo/models.py", line 3028, in read
    values[name] = field.convert_to_read(record[name], record, use_name_get)
  File "/opt/odoo/odoo/models.py", line 5232, in _getitem_
    return self._fields[key].__get__(self, type(self))
  File "/opt/odoo/odoo/fields.py", line 915, in _get_
    self.determine_value(record)
  File "/opt/odoo/odoo/fields.py", line 1027, in determine_value
    self.compute_value(recs)
  File "/opt/odoo/odoo/fields.py", line 981, in compute_value
    self._compute_value(records)
  File "/opt/odoo/odoo/fields.py", line 972, in _compute_value
    getattr(records, self.compute)()
  File "/opt/odoo/odoo/custom/henca_addons/henca_v10/sale_security/models/sale.py", line 11, in _compute_can_edit_so
    self.can_edit_so = self.env.user.has_group('sale_security.group_sale_security')
  File "/opt/odoo/odoo/fields.py", line 930, in _set_
    record.ensure_one()
  File "/opt/odoo/odoo/models.py", line 4844, in ensure_one
    raise ValueError("Expected singleton: %s" % self)
ValueError: Expected singleton: sale.order(7209, 2785)