Low Pass Hamming filter design

[LabWINC]

Hi all,
i have a question for all :-D

I would like to design and apply a FIR low pass filter with Hamming
window.
I'm using scipy module.

First I create the windows with the signal.firwin function and after i
apply this window to my signal with the signal.lfilter function.

I didn't understand where i can specify what kind of filter i'm
implementing (low, high or band pass).

Thanks all,

Vincenzo