How to make these histogram bars symmetric around its value?

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How to make these (integer-valued) histogram bars symmetric?

The output of

 sage: histogram([1,1,1,1,1,1,2,1,1,2,2,2,2,4,4,3,4])

is the plot below at whose. The bar at 1 is not centered, but shifted to the right; the bar at 4 is shifted to the left; the middle ones show milder shifts,

My primitive solution is to replace (don't laugh) by

 histogram([.85,.85,.85,.85,.85,.85,2,.85,.85,2,2,2,2,4.15,4.15,3,4.15])

to get what I wish:

How to do this properly?