docs: def method_or_name(namespace, x):
      '''
      If x is a ``str``, get ``namespace.x``.
  
      Otherwise, simply return ``x``.
      '''
      if not isinstance(x, str):
          return x
  
      if hasattr(namespace, x):
          return getattr(namespace, x)
  
      attrs = [y for y in dir(namespace) if not y.startswith('_')]
      msg = '''"%s" is not available in %s.
  These attributes are available: %s.''' % (x, namespace.__name__, attrs)
      raise AttributeError(msg)