It appears I was giving insufficient context to ctypes.
from ctypes import *
library = cdll.LoadLibrary('distribution/library/libhelpers.dylib')
class Service(object):
def __init__(self, port):
library.create_service.restype = c_void_p
self.obj = library.create_service(port)
def __del__(self):
library.release_service.argtypes = [c_void_p]
library.release_service(self.obj);