def values(self, *fields):
        """
        Ask the collection to return a list of dict of given fields for each
        instance found in the collection.
        If no fields are given, all "simple value" fields are used.
        """
        if not fields:
            fields = self._get_simple_fields()

        fields = self._coerce_fields_parameters(fields)

        self._instances = False
        self._values = {'fields': fields, 'mode': 'dicts'}
        return self