title: Copy oldest file to another directory using Python
body: <p>There are some problems in my python program.</p>
  
  <p>I want to open a directory, choose the oldest file and then copy the file to another directory.</p>
  
  <p>I read the documents where "shutil" is mentioned, but I don't know how to choose the oldest one.</p>
  
  <p>Could someone help me solve this problem?</p>