Should add option of minimum periods of none when there is a specific window size

[chen-bowen]

Right now, when I use the window = n, it requires me to have at least n entries without empty values. I believe it would be better if we use the amount of available data if the length is smaller than n. Right now it is returning NAN

[bsolomon1124]

Could you please give a small, reproducible example that we can take a look at?