code: def get_distinfo_file(self, path):
          
          # Check if it is an absolute path  # XXX use relpath, add tests
          if path.find(os.sep) >= 0:
              # it's an absolute path?
              distinfo_dirname, path = path.split(os.sep)[-2:]
              if distinfo_dirname != self.path.split(os.sep)[-1]:
                  raise DistlibException(
                      'dist-info file %r does not belong to the %r %s '
                      'distribution' % (path, self.name, self.version))
  
          # The file must be relative
          if path not in DIST_FILES:
              raise DistlibException('invalid path for a dist-info file: '
                                     '%r at %r' % (path, self.path))
  
          return os.path.join(self.path, path)
docs: Returns a path located under the ``.dist-info`` directory. Returns a
          string representing the path.
  
          :parameter path: a ``'/'``-separated path relative to the
                           ``.dist-info`` directory or an absolute path;
                           If *path* is an absolute path and doesn't start
                           with the ``.dist-info`` directory path,
                           a :class:`DistlibException` is raised
          :type path: str
          :rtype: str