input: Write a python function to translate French wikivoyage pages to English and vice versa.
  assert translate_wikivoyage('Paris', 'fr', 'en') == expected_output_for_paris_en
  assert translate_wikivoyage('Paris', 'en', 'fr') == expected_output_for_paris_fr
  assert translate_wikivoyage('New York', 'en', 'fr') == expected_output_for_new_york_fr
output: import requests
  
  def translate_wikivoyage(page_title, source_lang, target_lang):
      url = f"https://{source_lang}.wikivoyage.org/w/api.php"
      params = {
          "action": "query",
          "prop": "langlinks",
          "titles": page_title,
          "lllang": target_lang,
          "format": "json"
      }
  
      response = requests.get(url, params=params)
      data = response.json()
  
      page_id = next(iter(data['query']['pages']))
      langlinks = data['query']['pages'][page_id].get('langlinks', [])
      
      if langlinks:
          return langlinks[0]['*']
      else:
          return None