code: def _build_gadgets_rec(self, gadget_tree_root):
          
          root = gadget_tree_root.get_root()
          children = gadget_tree_root.get_children()
  
          node_list = []
  
          root_gadget_ins = root
  
          if not children:
              node_list += [[root_gadget_ins]]
          else:
              for child in children:
                  node_list_rec = self._build_gadgets_rec(child)
  
                  node_list += [n + [root_gadget_ins] for n in node_list_rec]
  
          return node_list
docs: Build a gadgets from a gadgets tree.