bounding_box() return a very small float number

[cecial]

hi, I am using cell.bounding_box function, but find it returns a very small float number, like following ((0.0,-4.440892098500626e-16), (174.142, 68.26))

which is supposed to be ((0.0,0.0), (174.142, 68.26))

is it a python issue? or gdstk issue? or can we round it to the gds library resultion?