title: How to delete row with timedelta value lower than 0?
body: <p>How can I delete rows which have values of timedelta &lt; 0:</p>
  
  <pre><code>Index     Date/Time               id           Timedelta
  8      2019-09-09 07:31:37.979  2555        0 days 00:40:00.033000
  9      2019-09-09 07:32:38.006  2555        0 days 00:01:00.027000
  10     2019-09-09 07:32:37.938  2555        -1 days +23:59:59.932000
  11     2019-09-09 11:22:38.154  2555        0 days 03:50:00.216000
  12     2019-09-09 13:04:38.138  2555        0 days 01:41:59.984000
  </code></pre>
  
  <p>Desired result is </p>
  
  <pre><code>Index     Date/Time               id           Timedelta
  8      2019-09-09 07:31:37.979  2555        0 days 00:40:00.033000
  9      2019-09-09 07:32:38.006  2555        0 days 00:01:00.027000
  11     2019-09-09 11:22:38.154  2555        0 days 03:50:00.216000
  12     2019-09-09 13:04:38.138  2555        0 days 01:41:59.984000
  </code></pre>
  
  <p>Thank you</p>