title: clone element with beautifulsoup
body: <p>I have to copy a part of one document to another, but I don't want to modify the document I copy from.</p>
  
  <p>If I use <code>.extract()</code> it removes the element from the tree. If I just append selected element like <code>document2.append(document1.tag)</code> it still removes the element from document1.</p>
  
  <p>As I use real files I can just not save document1 after modification, but is there any way to do this without corrupting a document?</p>