title: strange error in BS4. find_all() returns None
body: <p>I am using BS4 and PhantomJS for scraping a website. Everything works fine on Mac but on Windows I got a strange error: <code>find_all()</code> returns <code>None</code>, but the elements exists! </p>
  
  <p>My code:</p>
  
  <pre><code>def get_venues():
      driver = webdriver.PhantomJS(executable_path = path)
      url=web+'#/racing'
      driver.get(url)
      try:
          wait = WebDriverWait(driver,10).until(EC.presence_of_element_located((By.CLASS_NAME, "wrapper")))
      finally:
          content=driver.page_source
          soup=bs4.BeautifulSoup(content, "html5")
          driver.quit()
  
      b = soup.find(id='content').div
      print(b)
      c = b.ul(attrs={'class': 'main-list'})
  
      print(c)
  </code></pre>
  
  <p>and <code>c</code> is <code>None</code>, which should not be the case as <code>b</code> has:</p>
  
  <pre><code>&lt;/ul&gt;&lt;/div&gt;&lt;ul class="main-list"&gt;&lt;li&gt;&lt;div class="collapsible R"&gt;&lt;div class="icon race_code_R"&gt;&lt;/div&gt;&lt;span&gt;Thoroughbreds&lt;/span&gt;&lt;div class="arrow_down_sign"&gt;&lt;/div&gt;&lt;/div&gt;&lt;ul class="sub-list"&gt;&lt;li class="venue cell"&gt;&lt;a href="#/meetings/19197"&gt;
    &lt;span class="location"&gt;Beaudesert&lt;/span&gt;
    &lt;div class="goto-sign"&gt;&lt;/div&gt;
  &lt;/a&gt;
  &lt;a class="next-race" href="#/races/181880/exchange/win"&gt;
    &lt;span class="time-left critical"&gt;-30m&lt;/span&gt;
    &lt;span class="number"&gt;R5&lt;/span&gt;
  &lt;/a&gt;
  &lt;/li&gt;&lt;li class="venue cell"&gt;&lt;a href="#/meetings/19199"&gt;
    &lt;span class="location"&gt;Werribee&lt;/span&gt;
    &lt;div class="goto-sign"&gt;&lt;/div&gt;
  &lt;/a&gt;
  &lt;a class="next-race" href="#/races/181900/exchange/win"&gt;
    &lt;span class="time-left critical"&gt;-38s&lt;/span&gt;
    &lt;span class="number"&gt;R7&lt;/span&gt;
  &lt;/a&gt;
  &lt;/li&gt;&lt;li c
  </code></pre>