code: def recherche(self, pattern, entete, in_all=False):
          
          if in_all:
              self.collection = self.get_all()
          self.collection.recherche(pattern, entete)
          self._reset_render()
          return len(self.collection)
docs: abstractSearch in fields of collection and reset rendering.
          Returns number of results.
          If in_all is True, call get_all before doing the search.