docs: def get_template_dir():
      """Find and return the ntc-templates/templates dir."""
      try:
          template_dir = os.path.expanduser(os.environ["NET_TEXTFSM"])
          index = os.path.join(template_dir, "index")
          if not os.path.isfile(index):
              # Assume only base ./ntc-templates specified
              template_dir = os.path.join(template_dir, "templates")
      except KeyError:
          # Construct path ~/ntc-templates/templates
          home_dir = os.path.expanduser("~")
          template_dir = os.path.join(home_dir, "ntc-templates", "templates")
  
      index = os.path.join(template_dir, "index")
      if not os.path.isdir(template_dir) or not os.path.isfile(index):
          msg = """
  Valid ntc-templates not found, please install https://github.com/networktocode/ntc-templates
  and then set the NET_TEXTFSM environment variable to point to the ./ntc-templates/templates
  directory."""
          raise ValueError(msg)
      return os.path.abspath(template_dir)