This question is very similar to this SO, but my data is on the form:
'13-04-2018 14:06:26.866'
'13-04-2018 14:06:27.131'
'13-04-2018 14:06:27.404'
'13-04-2018 14:06:27.674'
...
i.e. the seconds are given as decimals. My reading of the datetime documentation suggests that it doesn't support this format, so I am not sure how to best proceed.