'Return all the distribution names known to this locator.'

def get_distribution_names(self):

    result = set()
    page = self.get_page(self.base_url)
    if (not page):
        raise DistlibException(('Unable    to    get    %s' % self.base_url))
    for match in self._distname_re.finditer(page.data):
        result.add(match.group(1))
    return result
