Create stacked histogram from unequal length arrays

Well, this is simple. I just need to put the three arrays in a list.

##Continued from above
###Now as three separate arrays
x1 = mu + sigma*np.random.randn(990,1)
x2 = mu + sigma*np.random.randn(980,1)
x3 = mu + sigma*np.random.randn(1000,1)

#Stack the data
plt.figure()
plt.hist([x1,x2,x3], bins, stacked=True, density=True)
plt.show()