title: BeautifulSoup find only elements where an attribute contains a sub-string? Is this possible?
body: <p>I have a call to <code>find_all()</code> in my <code>BeautifulSoup</code> code. This works currently to get me all images, but if I wanted to target only images which have a sub-string of "placeholder" in their <code>src</code>, how could I do this?</p>
  
  <pre><code>for t in soup.find_all('img'):  # WHERE img.href.contains("placeholder")
  </code></pre>