Make the default body of a Message an empty string instead of None, because AMQP doesn't distinguish between a zero-length body and something else like None.
Make the default body of a Message an empty string
instead of None, because AMQP doesn't distinguish
between a zero-length body and something else like None.

JustinTulloss/harelib,JustinTulloss/harelib,arnaudsj/py-amqplib