My dataframe looks like this:
Method Dataset          
A1     B2        10   20
       B3        10   20
       B1        10   20
       B1        10   20
A2     B2        10   20
       B1        10   20
A3     B9        10   20
       B5        10   20
The Dataset index is a string. How can I sort just the second (Dataset) index using a list like ["B1", "B2", "B3", "B4", "B5"] ? I think I'm looking for sortindex() but with custom ordering.
