error in Mstep

[cyzanfar]

Getting this error in M step:

<ipython-input-77-5107d679648f> in Mstep(self, weights)
     46 
     47         self.one.sigma = sqrt(sum(w * ((d - self.one.mean) ** 2)
---> 48                                   for (w, d) in zip(left, data)) / one_den)
     49         self.two.sigma = sqrt(sum(w * ((d - self.two.mean) ** 2)
     50                                   for (w, d) in zip(right, data)) / two_den)

TypeError: only size-1 arrays can be converted to Python scalars