docs: def link(origin, link_name, force=False, model_path=None):
      """
      Create a symlink for models within the spacy/data directory. Accepts
      either the name of a pip package, or the local path to the model data
      directory. Linking models allows loading them via spacy.load(link_name).
      """
      if util.is_package(origin):
          model_path = util.get_package_path(origin)
      else:
          model_path = Path(origin) if model_path is None else Path(model_path)
      if not model_path.exists():
          prints(Messages.M009.format(path=path2str(model_path)),
                 title=Messages.M008, exits=1)
      data_path = util.get_data_path()
      if not data_path or not data_path.exists():
          spacy_loc = Path(__file__).parent.parent
          prints(Messages.M011, spacy_loc, title=Messages.M010, exits=1)
      link_path = util.get_data_path() / link_name
      if link_path.is_symlink() and not force:
          prints(Messages.M013, title=Messages.M012.format(name=link_name),
                 exits=1)
      elif link_path.is_symlink():  # does a symlink exist?
          # NB: It's important to check for is_symlink here and not for exists,
          # because invalid/outdated symlinks would return False otherwise.
          link_path.unlink()
      elif link_path.exists(): # does it exist otherwise?
          # NB: Check this last because valid symlinks also "exist".
          prints(Messages.M015, link_path,
                 title=Messages.M014.format(name=link_name), exits=1)
      msg = "%s --> %s" % (path2str(model_path), path2str(link_path))
      try:
          symlink_to(link_path, model_path)
      except:
          # This is quite dirty, but just making sure other errors are caught.
          prints(Messages.M017, msg, title=Messages.M016.format(name=link_name))
          raise
      prints(msg, Messages.M019.format(name=link_name), title=Messages.M018)