Fixed - Pull 246 [Typo 'user' for 'usr'](https://github.com/sendgrid/sendgrid-python/pull/246) - Big thanks to [Mike Ralphson](https://github.com/MikeRalphson) for the pull request!
3.6.0
Added - Pull 234 [Substitutions allow non-strings for values](https://github.com/sendgrid/sendgrid-python/pull/234) - Big thanks to [ittus](https://github.com/ittus) for the pull request!
3.5.0
Added - Pull 233: [Allow dict to be passed to add_headers](https://github.com/sendgrid/sendgrid-python/pull/233) - Big thanks to [Navin Pai](https://github.com/navinpai) for the pull request!
3.4.0
Added - Pull 215 - Support larger files. Note that there is a 20MB maximum.
3.3.1
Fixed - Pull 213 - Naming inconsistency, we now standardized on `file_name` - Support for use of `iteritems` in Python 3