code: def list_datasets():
      
      lines = []
      for name, resource in itertools.chain(LOCAL_DATASETS.items(), REMOTE_DATASETS.items()):
  
          if isinstance(resource, LocalFileMetadata):
              location = "local: {}".format(resource.filename)
          elif isinstance(resource, RemoteFileMetadata):
              location = "remote: {}".format(resource.url)
          else:
              location = "unknown"
          lines.append("{}\n{}\n{}\n{}".format(name, "=" * len(name), resource.description, location))
  
      return "\n\n{}\n\n".format(10 * "-").join(lines)
docs: Get a string representation of all available datasets with descriptions.