docs: def generators():
      """
      List all the available generators.
      """
      from populous import generators
  
      base = generators.Generator
  
      for name in dir(generators):
          generator = getattr(generators, name)
  
          if isinstance(generator, type) and issubclass(generator, base):
              name = generator.__name__
              doc = (generator.__doc__ or '').strip()
  
              if doc:
                  click.echo("{} - {}".format(name, doc))
              else:
                  click.echo(name)