File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/view/form_gtk/many2one.py", line 238, in sig_edit
    WinForm(screen, callback, save_current=True)

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/win_form.py", line 33, in __init__
    self.screen.switch_view(view_type=view_type)

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/screen/screen.py", line 340, in switch_view
    if self.current_record and not self.current_record.validate(fields):

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/model/record.py", line 380, in validate
    if not field.validate(self, softvalidation):

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/model/field.py", line 89, in validate
    inverted_domain, domain = self.validation_domains(record)

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/model/field.py", line 431, in validation_domains
    screen_domain, attr_domain = self.domains_get(record)

  File "/usr/local/lib/python2.7/dist-packages/tryton/gui/window/view_form/model/field.py", line 49, in domains_get
    self.name, EvalEnvironment(record))

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 192, in domain_inversion
    return expression.inverse(symbol, context)

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 216, in inverse
    part_inversion = part.inverse(symbol, context)

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 230, in inverse
    and eval_leaf(part, context, operator.and_)):

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 83, in eval_leaf
    return OPERATORS[operand](context_field, value)

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 23, in <lambda>
    'not in': lambda a, b: not in_(b, a),

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 11, in in_
    return any(operator.contains(b, x) for x in a)

  File "/usr/local/lib/python2.7/dist-packages/tryton/common/domain_inversion.py", line 11, in <genexpr>
    return any(operator.contains(b, x) for x in a)