title: Convert Timestamp string date to datetime python
body: <p>My dataframe contains the column 'date' which is in the format of '2020-01-21 10:00:00'.
  I want to add an additional column 'day' which will contain the day of the date.
  I'm having a problem converting a date to a day because of the timestamp.
  When I execute this code: my_data['date'][0], it outputs Timestamp('2020-01-21 10:00:00'), which prevents me from using datetime method of conversion.</p>
  <p>Is there any way to solve this problem?
  Thank you.</p>