code: 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
docs: Return all the distribution names known to this locator.