title: Python sched module only works when the time is past otherwise it crashes
body: <p>When I run this code</p>
  <pre><code>import sched,time,webbrowser
  
  def action():
  webbrowser.open(&quot;https://www.youtube.com/watch?v=dQw4w9WgXcQ&quot;)
  
  a = time.strptime('Thu Jan 27 21:25:30 2022')
  
  s = sched.scheduler(time.localtime, time.sleep)
  s.enterabs(a, 0,action)
  s.run()
  </code></pre>
  <p>it only works when the given time is past the current time if it isn't, I get this error</p>
  <pre><code>TypeError: unsupported operand type(s) for -: 'time.struct_time' and 'time.struct_time'
  </code></pre>
  <p>What is causing this problem and how can I solve it?</p>