def maybe_unwrap_index(obj):
if isinstance(obj, ABCIndexClass):<EOL><INDENT>return obj._data<EOL><DEDENT>return obj<EOL>
If operating against another Index object, we need to unwrap the underlying
data before deferring to the DatetimeArray/TimedeltaArray/PeriodArray
implementation, otherwise we will incorrectly return NotImplemented.

Parameters
----------
obj : object

Returns
-------
unwrapped object