tab_section.py

class TabSection(Directive):
    has_content = True  # this directive can have children
    required_arguments = 1  # has 1 arg
    optional_arguments = 0
    
     # add a kwarg `keyworks` these are used for search
    option_spec = {'keywords': directives.unchanged} 
    
    # we need a new line after the args before the child content
    final_argument_whitespace = True

    def run(self):
        """
        This function is called when sphinx builds an AST out of the source files.
        Should return a list of nodes for the AST that will be appended in this location.
        """
        keywords = self.options.get('keywords', None)
        if keywords is not None and len(keywords) > 0:
            keywords = keywords.split(' ')
        else:
            keywords = []
        
        # we need to create some things inside this AST
        node = Element()
        node.document = self.state.document
        
        # build the AST for the child content
        nested_parse_with_titles(self.state, self.content, node)
        
        # get the tab's title
        title = self.arguments[0]
        
        # use the node we set up
        # (this is another class not shown here that subclasses Frame)
        frame = TabFrameNode(
          title=title,
          ids=[title.replace(' ', '_')],
          names=[title],
          index_keywords=keywords
        )
        frame += nodes.title(text=title)
        for child in node:
            if isinstance(child, TabNode):
                frame.append(child)
        return [frame]