Suppose I have a DataFrame with a MultiIndex as follows:

```
                             col  col  col  col ...
tstp                    pkt                                                   
2016-04-14 04:05:32.321 0    ...  ...  ...  ...
                        25   ...  ...  ...  ...
2016-04-14 04:05:32.322 1    ...  ...  ...  ...   
                        26   ...  ...  ...  ...  
2016-04-14 04:05:32.374 2    ...  ...  ...  ...
...

```

Once I determine `beg` and `end`, I'd like to use the `df[].between_time(beg,end)` to grab the relevant rows from the DataFrame. Only problem is, `.between_time(beg,end)` seems to work only on a DateTimeIndex:

```
*** TypeError: Index must be DatetimeIndex

```

Or is the more appropriate way to do this via `xs()`?

```
df.xs(slice(beg,end),level='tstp')

```