docs: def siteblock(parser, token):
      """Two notation types are acceptable:
  
          1. Two arguments:
             {% siteblock "myblock" %}
             Used to render "myblock" site block.
             
          2. Four arguments:
             {% siteblock "myblock" as myvar %}
             Used to put "myblock" site block into "myvar" template variable.
             
      """
      tokens = token.split_contents()
      tokens_num = len(tokens)
  
      if tokens_num not in (2, 4):
          raise template.TemplateSyntaxError(
              '%r tag requires two or four arguments. '
              'E.g.: {%% siteblock "myblock" %%} or {%% siteblock "myblock" as myvar %%}.' % tokens[0])
  
      block_alias = parser.compile_filter(tokens[1])
      as_var = None
      tokens = tokens[2:]
      if len(tokens) >= 2 and tokens[-2] == 'as':
          as_var = tokens[-1]
  
      return siteblockNode(block_alias, as_var)