code: def validate_episode(episode):
      src_dir = os.path.join(get_tutorials_dir(), episode)
      if not os.path.isdir(src_dir):
          raise click.BadArgumentUsage(
              "Episode "
              + click.style('"{0}"'.format(episode), fg="red")
              + " does not exist."
              " To see a list of available episodes, "
              "type:\n"
              + click.style("metaflow tutorials list", fg="cyan")
          )
  
file_path: metaflow/metaflow/cmd/tutorials_cmd.py
imports: import os
  import shutil
  from metaflow._vendor import click
  from .util import echo_always, makedirs
label_desc: Use image node_id 7 for calling a global function with example usage: validate_episode(episode) without return types