boto/boto — pull request #1593 by jimbrowne (2013-07-08 21:16:32+00:00)
Title: SQS messages support for Python 'in' keyword

Noticed that SQS messages are not supporting the 'in' keyword due to lacking a __contains__ method and the fall-back method of integer iteration of __getitem__ is nonsensical for this data type. I don't believe an __iter__ method is needed, so leaving that out.