derivatives not working: cpp conversion error

[zullu14]

Hi,
When trying to run any of the synthetic functions or my own functions using the observations of fun. derivatives,
I'm getting the following error:

Traceback (most recent call last):
File "/home/User/ENV_CMOE/lib/python3.6/site-packages/emcee/ensemble.py", line 505, in call
return self.f(x, *self.args, **self.kwargs)
File "/home/User/Cornell-MOE/moe/optimal_learning/python/cpp_wrappers/log_likelihood_mcmc.py", line 310, in compute_log_likelihood
cpp_utils.cppify(noise),
TypeError: No registered converter was able to produce a C++ rvalue of type int from this Python object of type numpy.int64

I'm changing the self._observations to numpy.arange(self._dim) instead of []. I've noticed that a similar issue is mentioned
in Issue #63 , but unfortunately, a proposed workaround with [float(x) for x in ...] doesn't work. Has anybody encountered a similar problem or knows how to fix this?