If you have a datetime as a string you can transform it into a datetime object using the strptime method from datetime module in python.
Strptime receive to string parameters: date interpretation and date format:
#!/usr/bin/env python
from datetime import datetime
given_date = '11/23/2018 14:20:24'
date_object = datetime.strptime(given_date, '%m/%d/%Y %H:%M:%S')
If you want to change the date format on display, you'll have to use strftime (note f instead of p in the middle of the word)
shown_date = date_object.strftime('%Y-%M-%D %H:%M:%S')