Tryton Override searcher

     def search_state(cls, name, clause):
          result = super(PurchaseRequest, cls).search_state(name, clause)
          # result contains [('id', 'in', state_query)]
          _, _, state_query = result[0]
          # state query is a python-sql which can be manipullated
          state_query.where &= new_condition  # To add new where
          # If required you can join to new tables
          new_query = state_query.join()
          # Or enterly replace the wer
          new_query.where = new_where
          # Once you have customized the query you can return it
          return [('id', 'in', new_query)]
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