gistfile1.py

    def filter(self, **kwargs):
        """
        Update self so that __iter__ returns a generator that yields a filtered
        set of C{ReadAlignments}.

        See self._filter for details of arguments.

        @return: C{self}.
        """
        iterator = self._filter(selfIterator=self.__iter__, **kwargs)
        self.__iter__ = lambda _: iterator
        return self