code: def start_node(tag: str):
      """Add a new node to profiling
  
      Args:
          tag (str): name of new node
      """
      profiling = ctx.profiling
      new_node = {
          "start_at": time.perf_counter(),
          "start_at_thread": time.thread_time(),
          "start_at_process": time.process_time(),
          "stop_at": None,
          "name": tag,
          "children": [],
      }
      if profiling["pointer"] is None:
          if profiling["level"] != 1:
              # profiling was activated not in the root of nodes tree
              return
          profiling["pointer"] = []
          profiling["tree"] = new_node
          profiling["tree"]["time_start_at"] = datetime.now(
              timezone.utc
          )
      else:
          current_node = _get_current_node(profiling)
          profiling["pointer"].append(len(current_node["children"]))
          current_node["children"].append(new_node)
  
imports: import time
  from datetime import datetime, timezone
  from functools import wraps
  import mindsdb.utilities.hooks
  from mindsdb.utilities.config import Config
  from mindsdb.utilities.context import context
label_desc: Use image node_id 2 for calling a global function with example usage: start_node(tag) without return types