Code review comment for lp:~djfroofy/txaws/newagent-767205

Sorry for the delay. Looks good to me.

Just a minor style nit: some of the code indents parameters to after the '(', and some only by 4 spaces. E.g.
{{{
def __init__(self, creds=None, endpoint=None, query_factory=None,
             parser=None, receiver_factory=None):
}}}
vs
{{{
def __init__(self, creds=None, endpoint=None, query_factory=None,
    receiver_factory=None):
}}}
The former is more readable.