content: class NotInstalled:
      """
      This object is used for optional dependencies. If a backend is not installed we
      replace the transformer/language with this object. This allows us to give a friendly
      message to the user that they need to install extra dependencies as well as a link
      to our documentation page.
      """
  
      def __init__(self, tool, dep):
          self.tool = tool
          self.dep = dep
  
          msg = f"In order to use {self.tool} you'll need to install via;\n\n"
          msg += f"pip install whatlies[{self.dep}]\n\n"
          msg += "See installation guide here: https://koaning.github.io/whatlies/#installation."
          self.msg = msg
  
      def __getattr__(self, *args, **kwargs):
          raise ModuleNotFoundError(self.msg)
  
      def __call__(self, *args, **kwargs):
          raise ModuleNotFoundError(self.msg)
  