res.users からの sucursal のみが必要で、取得方法がわかりません。
def _user_sucursal(self, cr, uid, ids, field, arg, context = None):
suc = self.pool.get('res.users')
ids = suc.search (cr, uid, [])
res = suc.read(cr, uid, ids, ['id'],['sucursal_u'], context)
res = [(r['id'], r['sucursal']) for r in res]
return res