Worksheet.append should accept an iterator
Created originally on Bitbucket by scott_stanton_veeva (Scott Stanton)
Currently Worksheet.append only accepts list, tuple, range or generators (or dict). This means it does not accept iterators like itertools.chain(). Instead of testing explicit types, it should just use a try/except block items(), falling back to enumerate() in another try/except block so that it can accept anything enumerate() will accept.