I have a pandas dataframe 'df' with a column 'DateTimes' of type datetime.time.

The entries of that column are hours of a single day:

```
00:00:00
.
.
.
23:59:00

```

Seconds are skipped, it counts by minutes.

How can I choose rows by hour, for example the rows between 00:00:00 and 00:01:00?

---

If I try this: 

```
df.between_time('00:00:00', '00:00:10')

```

I get an error that index must be a DateTimeIndex.

I set the index as such with:

```
df=df.set_index(keys='DateTime')

```

but I get the same error. 

I can't seem to get 'loc' to work either. Any suggestions?