@rule('<STR_LIT>')<EOL><INDENT>def visit_first_filter(self, _, children):<DEDENT>
return children[<NUM_LIT:0>]<EOL>
The first filter, so not preceded by a dot.

        Arguments
        ---------
        _ (node) : parsimonious.nodes.Node.
        children : list
            - 0: A``Filter`` resource.

        Returns
        -------
        .resources.Filter
            An instance of ``Filter``.

        Example
        -------

        >>> FiltersParserMixin('foo', default_rule='FIRST_FILTER').data
        .foo