from spectrum import bicoherence
bicoherence(y, nfft=None, wind=None, nsamp=None, overlap=None)
from spectrum import bicoherencex
bicoherencex(w, x, y, nfft=None, wind=None, nsamp=None, overlap=None)
from spectrum import bispectrumd
bispectrumd(y, nfft=None, wind=None, nsamp=None, overlap=None)
from spectrum import bispectrumi
bispectrumi(y, nlag=None, nsamp=None, overlap=None, flag='biased', nfft=None, wind=None)
from spectrum import bispectrumdx
bispectrumdx(x, y, z, nfft=None, wind=None, nsamp=None, overlap=None)
from spectrum import cumest
order = 2 # 2nd order
cumest(y, norder=order, maxlag=0 ,nsamp=None, overlap=0, flag='biased' ,k1=0, k2=0)
from spectrum import cum2x, cum3x, cum4x
cum2x(x, y, maxlag=0, nsamp=0, overlap=0, flag='biased')
cum3x(x, y, z, maxlag=0, nsamp=0, overlap=0, flag='biased', k1=0)
cum4x(w, x, y, z, maxlag=0, nsamp=0, overlap=0, flag='biased', k1=0, k2=0)
More coming soon
Taken from the Higher Order Spectral Analysis toolkit for MATLAB