def query_unique(self, field):
        """Return a list of unique values appearing in the journal for the given
        `field`.

        Note this does not respect any journal matches.

        Entries will be processed with converters specified during
        Reader creation.
        """
        return set(self._convert_field(field, value)
                   for value in super(Reader, self).query_unique(field))
Return a list of unique values appearing in the journal for the given
        `field`.

        Note this does not respect any journal matches.

        Entries will be processed with converters specified during
        Reader creation.