input: Write a python function to parse HTML and extract text content using BeautifulSoup.
  assert parse_html('<html><body><p>Hello, World!</p></body></html>') == 'Hello, World!'
  assert parse_html('<div><h1>Title</h1><p>Paragraph.</p></div>') == 'Title\nParagraph.'
  assert parse_html('<span>Text<span><div>More text</div>') == 'TextMore text'
output: def parse_html(html):
      from bs4 import BeautifulSoup
      soup = BeautifulSoup(html, 'html.parser')
      return soup.get_text(separator='\n').strip()