docs: def style_node(self, additional_style_attrib=None):
          """
          generate a style node (for automatic-styles)
  
          could specify additional attributes such as
          'style:parent-style-name' or 'style:list-style-name'
  
          """
          style_attrib = {"style:name": self.name, "style:family": self.FAMILY}
          if additional_style_attrib:
              style_attrib.update(additional_style_attrib)
          if self.PARENT_STYLE_DICT:
              style_attrib.update(self.PARENT_STYLE_DICT)
  
          node = el("style:style", attrib=style_attrib)
          props = sub_el(node, self.STYLE_PROP, attrib=self.styles)
          return node