I'm using black and isort for other projects (see e.g. https://github.com/hyperopt/hyperopt/pull/748/files) and find them quite useful to have more consistent codebase. I think you should drop python3.5 support though, as black is python3.6+. Is this something you would be open to consider?

Is your feature request related to a problem? Please describe.

Currently, the MultiIndex schema component str representation is the same as
the DataFrameSchema representation

Describe the solution you'd like

the MultiIndex schema component should implement its own str representation
so that it doesn't render columns and instead shoulds the indexes.

• Display the index of series or DataFrame similar to Pandas
  Example:

>>> pd_flights.index
Index(['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
       ...
       '13049', '13050', '13051', '13052', '13053', '13054', '13055', '13056',
       '13057', '13058'],
      dtype='object', length=13059)

>>> pd_flights["AvgTicketPrice"].index
Index(['0', '1', '2', '3', '4', '5', '6

Code coverage should be added to the Travis config (perhaps the cabal file and/or the stack options need to be changed in order to account for hpc coverage generation); currently in Travis there is only a project key.
This tool uploads hpc coverage reports to codecov.io .

Add DateTime and similar

• Heidi instances
• lenses