def xpath_even_pseudo(self, xpath):
        # the first element is 1 in xpath and 0 in python and js
        xpath.add_post_condition('position() mod 2 = 1')
        return xpath
Matches even elements, zero-indexed::
dataset/ETHPy150Open gawel/pyquery/pyquery/cssselectpatch.py/JQueryTranslator.xpath_even_pseudo