code: def test_merge_formatted_text():
      html1 = HTML("<u>hello</u>")
      html2 = HTML("<b>world</b>")
      result = merge_formatted_text([html1, html2])
  
      assert to_formatted_text(result) == [
          ("class:u", "hello"),
          ("class:b", "world"),
      ]
  
file_path: catboost/contrib/python/prompt-toolkit/py3/tests/test_formatted_text.py
imports: from __future__ import annotations
  from prompt_toolkit.formatted_text import ANSI, HTML, FormattedText, PygmentsTokens, Template, merge_formatted_text, to_formatted_text
  from prompt_toolkit.formatted_text.utils import split_lines
label_desc: Use image node_id 9 for calling a global function with example usage: test_merge_formatted_text() without return types