current implementation was breaking making the module unusable, changing to the list comprehension fixes this. Also default to seconds instead of throwing a exception when no duration units are supplied as this causes tests to fail
PR #1299 introduced the service_address parameter but specified a
default value of localhost. This is a breaking change; prior to that,
the consul module would always assume that the service should advertise
the address that the Consul agent was listening on. With this change,
the consul module will now default to advertising localhost to all nodes
for the service, which isn't the desired behavior. This changes the
default back to None which is the implicit default prior to #1299.
Some do not use the json module directly so don't need import json.
Some needed to fallback to simplejson with no traceback if neither was installed
Fixes#1298
