seq

ERROR:tryton.common.common:Traceback (most recent call last):
  File "/trytond/protocols/jsonrpc.py", line 125, in _marshaled_dispatch
    response['result'] = dispatch_method(method, params)
  File "/trytond/protocols/jsonrpc.py", line 158, in _dispatch
    res = dispatch(*args)
  File "/trytond/protocols/dispatcher.py", line 158, in dispatch
    result = rpc.result(meth(*c_args, **c_kwargs))
  File "/trytond/modules/carrier_company/carrier_company.py", line 162, in create
    vals['reference'] = Sequence.get_id(sequence.id)
AttributeError: 'NoneType' object has no attribute 'id'