code: def delete(self,removed):
          
          if isinstance(removed,dict):
              # remove a single record
              removed = [removed]
          else:
              # convert iterable into a list (to be able to sort it)
              removed = [ r for r in removed ]
          if not removed:
              return 0
          _ids = [ r['__id__'] for r in removed ]
          _ids.sort()
          sql = "DELETE FROM %s WHERE __id__ IN (%s)" %(self.name,
              ",".join([str(_id) for _id in _ids]))
          self.cursor.execute(sql)
          return len(removed)
docs: Remove a single record, or the records in an iterable
          Before starting deletion, test if all records are in the base
          and don't have twice the same __id__
          Return the number of deleted items