input: Write a python function to extract text data from a given URL using requests and lxml libraries.
  assert extract_text('http://example.com/') == ["Example Domain", "illustrative examples in documents.", "More information..."]
  assert extract_text('http://anotherexample.com/') == ["Another Example Domain", "More illustrative examples.", "Additional information..."]
output: def extract_text(url):
      import requests
      from lxml import html
      
      response = requests.get(url)
      tree = html.fromstring(response.content)
      text_elements = tree.xpath('//text()')
      return [text.strip() for text in text_elements if text.strip()]