Single records must be called with an iterator

[mrmiguez]

In [2]: rec = pymods.MODSReader('FSU_ARHHouse_1018.xml')

In [3]: rec.
rec.close                      rec.makeelement
rec.copy                      rec.resolvers
rec.error_log                rec.setElementClassLookup
rec.feed                       rec.set_element_class_lookup
rec.feed_error_log        rec.target
rec.iterator                  rec.version

In [3]: mods = next(rec)

In [4]: mods.tag
Out[4]: '{http://www.loc.gov/mods/v3}mods'

[mrmiguez]

Implementing __index__ and __len__ would allow for testing reader size. Reader could return next(obj) if it's len is 1.