Cannot succesfully copy kmeans trainers!

See the code below to reproduce:

In [2]: import bob.learn.em

In [3]: bob.learn.em
Out[3]: <module 'bob.learn.em' from 'src/bob.learn.em/bob/learn/em/__init__.py'>
# bob.learn.em from master

In [4]: trainer1 = bob.learn.em.KMeansTrainer()

In [6]: machine = bob.learn.em.KMeansMachine(3, 2)

In [7]: trainer1.reset_accumulators(machine)

In [8]: trainer1.zeroeth_order_statistics
Out[8]: array([0., 0., 0.])

In [9]: trainer2 = bob.learn.em.KMeansTrainer(trainer1)

In [10]: trainer2.zeroeth_order_statistics
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-10-35fe1ff0cedc> in <module>()
----> 1 trainer2.zeroeth_order_statistics

ValueError: cannot convert C++ blitz::Array<float64,1> which doesn't behave (memory contiguous, aligned, C-style) into a pythonic bob.blitz.array