def lowpass_filter(data, cutoff, fs, order=<NUM_LIT:5>):
nyq = <NUM_LIT:0.5> * fs<EOL>normal_cutoff = cutoff / nyq<EOL>b, a = signal.butter(order, normal_cutoff, btype='<STR_LIT>', analog=False)<EOL>y = signal.lfilter(b, a, data)<EOL>return y<EOL>
Does a lowpass filter over the given data.

:param data: The data (numpy array) to be filtered.
:param cutoff: The high cutoff in Hz.
:param fs: The sample rate in Hz of the data.
:param order: The order of the filter. The higher the order, the tighter the roll-off.
:returns: Filtered data (numpy array).