def _get_index_urls_locations(self, project_name):
        """Returns the locations found via self.index_urls

        Checks the url_name on the main (first in the list) index and
        use this url_name to produce all locations
        """

        def mkurl_pypi_url(url):
            loc = posixpath.join(url, project_url_name)
            # For maximum compatibility with easy_install, ensure the path
            # ends in a trailing slash.  Although this isn't in the spec
            # (and PyPI can handle it without the slash) some other index
            # implementations might break if they relied on easy_install's
            # behavior.
            if not loc.endswith('/'):
                loc = loc + '/'
            return loc

        project_url_name = urllib_parse.quote(project_name.lower())

        if self.index_urls:
            # Check that we have the url_name correctly spelled:

            # Only check main index if index URL is given
            main_index_url = Link(
                mkurl_pypi_url(self.index_urls[0]),
                trusted=True,
            )

            page = self._get_page(main_index_url)
            if page is None and str(main_index_url) not in PyPI.netloc:
                warnings.warn(
                    "Failed to find %r at %s. It is suggested to upgrade "
                    "your index to support normalized names as the name in "
                    "/simple/{name}." % (project_name, main_index_url),
                    RemovedInPip8Warning,
                )

                project_url_name = self._find_url_name(
                    Link(self.index_urls[0], trusted=True),
                    project_url_name,
                ) or project_url_name

        if project_url_name is not None:
            return [mkurl_pypi_url(url) for url in self.index_urls]
        return []
dataset/ETHPy150Open anzev/hedwig/build/pip/pip/index.py/PackageFinder._get_index_urls_locations/swapped operands of `not in`