Opens multiple files specified by given path-specs.

  See documentation for `VFSOpen` for more information.

  Args:
    pathspecs: A list of pathspec instances of files to open.
    progress_callback: A callback function to call to notify about progress

  Returns:
    A context manager yielding file-like objects.

def VFSMultiOpen(pathspecs, progress_callback=None):
  """Opens multiple files specified by given path-specs.

  See documentation for `VFSOpen` for more information.

  Args:
    pathspecs: A list of pathspec instances of files to open.
    progress_callback: A callback function to call to notify about progress

  Returns:
    A context manager yielding file-like objects.
  """
  precondition.AssertIterableType(pathspecs, rdf_paths.PathSpec)

  vfs_open = functools.partial(VFSOpen, progress_callback=progress_callback)
  return context.MultiContext(map(vfs_open, pathspecs))