Ti.tema(input,period)

Hi,
I tried to calculate tema 9 and tema 21 my commands were:
tema9 = ti.tema(data.close.to_numpy(), 9)[-1]
tema21 = ti.tema(data.close.to_numpy(), 21)[-1]

Where data was loaded from historical data.
The first command line went through fine, but the second command had an error: tulipy.lib.InvalidOptionError. I tried to change to different period and found out that any number =< 15 the command worked fine; any period > 15 returned error.

Would any one help to confirm this is the limit for Ti.tema and would you help with a work-around solution?

Thank you very much,

Thao

I figured out that we need more data point to compute long period