docs: def get_info(self, location):
          """Returns (url, revision), where both are strings"""
          assert not location.rstrip('/').endswith(self.dirname), 'Bad directory: %s' % location
          output = call_subprocess(
              [self.cmd, 'info', location], show_stdout=False, extra_environ={'LANG': 'C'})
          match = _svn_url_re.search(output)
          if not match:
              logger.warn('Cannot determine URL of svn checkout %s' % display_path(location))
              logger.info('Output that cannot be parsed: \n%s' % output)
              return None, None
          url = match.group(1).strip()
          match = _svn_revision_re.search(output)
          if not match:
              logger.warn('Cannot determine revision of svn checkout %s' % display_path(location))
              logger.info('Output that cannot be parsed: \n%s' % output)
              return url, None
          return url, match.group(1)