code: def add_child_span(self, span: "Span") -> None:
      if self.child_spans is None:
          self.child_spans = []
      self.child_spans.append(span)
  
imports: import dataclasses
  import hashlib
  import json
  import typing
  from dataclasses import dataclass, field
  from enum import Enum
  from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
  import wandb
  import wandb.data_types
  from wandb.sdk.data_types import _dtypes
  from wandb.sdk.data_types.base_types.media import Media
label_desc: Use image node_id 3 for calling the Span obj's underlying member method code with example usage: obj.add_child_span(span) without return types