code: def test_trace_add_child():
      parent_trace = Trace(
          name="parent_trace", kind="LLM", status_code="SUCCESS"
      )
      child_trace = Trace(
          name="child_trace", kind="LLM", status_code="SUCCESS"
      )
  
      parent_trace.add_child(child_trace)
  
      assert child_trace._span in parent_trace._span.child_spans
  
imports: import time
  import pytest
  from wandb.sdk.data_types.trace_tree import Span, SpanKind, StatusCode, Trace
label_desc: Use image node_id 4 for calling a global function with example usage: test_trace_add_child() without return types