Error keyword argument 'mmap_mode'

Development
1

Hi All,
I have a Normal Mixture model. When I do the sampling I get this error:

File "/usr/local/lib/python2.7/dist-packages/pymc3/sampling.py", line 439, in sample
trace = _mp_sample(**sample_args)
File "/usr/local/lib/python2.7/dist-packages/pymc3/sampling.py", line 1032, in _mp_sample
traces = Parallel(n_jobs=cores, mmap_mode=None)(jobs)
TypeError: __init__() got an unexpected keyword argument 'mmap_mode'

My version of
python: 2.7.16
pymc3: 3.6
scipy: 1.2.1
numpy: 1.15.4
theano: 1.0.4

Ubuntu:

Distributor ID: Ubuntu
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Codename: trusty

The code that generates the error:

def test2():
 SEED = 383561
 np.random.seed(SEED) # from random.org, for reproducibility
 N = 1000
 W = np.array([0.35, 0.4, 0.25])	
 MU = np.array([0., 2., 5.])
 SIGMA = np.array([0.5, 0.5, 1.])
 component = np.random.choice(MU.size, size=N, p=W)
 x = np.random.normal(MU[component], SIGMA[component], size=N)
 idx_arr = []
 with pm.Model() as model:
 	k = 3
	arr = []
	for j in range(k):
		arr.append(pm.Uniform('a'+str(j),lower=0,upper=0.99))

	w = pm.Dirichlet('w', a=tt.stack([arr[i] for i in range(k)]), shape=k)
	du = pm.DiscreteUniform('du',lower=0, upper=1,shape=k)
	
	idx_arr = []
	for i in range(k):
		if du[i]:
			idx_arr.append(i)

	mu = pm.Normal('mu', 0., 10., shape=k)
	tau = pm.Gamma('tau', 1., 1., shape=k)
	
	x_obs = pm.NormalMixture('x_obs', tt.stack([ w[h] for h in idx_arr ]), tt.stack([ mu[h] for h in idx_arr ]), tau=tt.stack([ tau[h] for h in idx_arr ]), observed=x)
	
	
with model:	
	trace = pm.sample(3000,n_init=10000, tune=500, random_seed=SEED)[1000:]

Any idea what the error is about?
Thanks

2

FYI for those are interested: https://github.com/pymc-devs/pymc3/issues/3438