code: def test_header():
      script = AppTest.from_string(
          """
          import streamlit as st
  
          st.header("This is a header")
          st.header("This is a header with anchor", anchor="header anchor text")
          st.header("This is a header with hidden anchor", anchor=False)
          """,
      )
      sr = script.run()
  
      assert len(sr.header) == 3
      assert sr.header[1].tag == "h2"
      assert sr.header[1].anchor == "header anchor text"
      assert sr.header[1].value == "This is a header with anchor"
      assert sr.header[2].hide_anchor
  
      repr(sr.header[0])
  
imports: from datetime import date, datetime, time
  import numpy
  import pandas
  import pytest
  from streamlit.elements.markdown import MARKDOWN_HORIZONTAL_RULE_EXPRESSION
  from streamlit.testing.v1.app_test import AppTest
label_desc: Use image node_id 12 for calling a global function with example usage: test_header() without return types