Servicenow response upon deleteMultiple query

[Gloix]

I'm using the JSONv2 API like the following:

from servicenow import Utils
from servicenow import ServiceNow
some_set_id = ...
sys_history_line = ServiceNow.Base(my_connection)
sys_history_line.__table__ = "sys_history_line.do"
history_lines_query = Utils.format_query({ "set": some_set_id })
sys_history_line.delete_multiple(history_lines_query)

It throws a JSON decoding exception, but upon further inspection the response returned by my Kingston instance is:

{"records":[{"count":0}{"records":[]}

Which is not well formatted. Is the API faulty or the way of querying not right?