How to use the cssselect.parser.parse function in cssselect

"""Translate a *group of selectors* to XPath.

        Pseudo-elements are not supported here since XPath only knows
        about "real" elements.

        :param css:
            A *group of selectors* as an Unicode string.
        :raises:
            :class:`SelectorSyntaxError` on invalid selectors,
            :class:`ExpressionError` on unknown/unsupported selectors,
            including pseudo-elements.
        :returns:
            The equivalent XPath 1.0 expression as an Unicode string.

        """
        selectors = parse(css)
        for selector in selectors:
            if selector.pseudo_element:
                raise ExpressionError('Pseudo-elements are not supported.')

        return ' | '.join(
            self.selector_to_xpath(selector, prefix)
            for selector in selectors)

:param css:
            A *group of selectors* as an Unicode string.
        :param prefix:
            This string is prepended to the XPath expression for each selector.
            The default makes selectors scoped to the context node’s subtree.
        :raises:
            :class:`SelectorSyntaxError` on invalid selectors,
            :class:`ExpressionError` on unknown/unsupported selectors,
            including pseudo-elements.
        :returns:
            The equivalent XPath 1.0 expression as an Unicode string.

        """
        return ' | '.join(self.selector_to_xpath(selector, prefix,
                                                 translate_pseudo_elements=True)
                          for selector in parse(css))

:param css:
            A *group of selectors* as an Unicode string.
        :param prefix:
            This string is prepended to the XPath expression for each selector.
            The default makes selectors scoped to the context node’s subtree.
        :raises:
            :class:`SelectorSyntaxError` on invalid selectors,
            :class:`ExpressionError` on unknown/unsupported selectors,
            including pseudo-elements.
        :returns:
            The equivalent XPath 1.0 expression as an Unicode string.

        """
        return ' | '.join(self.selector_to_xpath(selector, prefix,
                                                 translate_pseudo_elements=True)
                          for selector in parse(css))