input: Write a function to extract all text content from an HTML document using BeautifulSoup.
  assert extract_text_from_html("<html><body><h1>Test</h1></body></html>") == ["Test"]
  assert extract_text_from_html("<html><body><div><p>Para 1</p><p>Para 2</p></div></body></html>") == ["Para 1", "Para 2"]
  assert extract_text_from_html("<html><head><title>Title</title></head><body><h1>Header</h1><p>Paragraph</p></body></html>") == ["Title", "Header", "Paragraph"]
output: def extract_text_from_html(html_doc):
      from bs4 import BeautifulSoup
  
      soup = BeautifulSoup(html_doc, 'html.parser')
      return [element.get_text() for element in soup.find_all(text=True) if element.strip()]