def acovf_explicit(ar, ma, nobs):
 ir = arma_impulse_response(ar, ma)
 acovfexpl = [np.dot(ir[:(nobs - t)], ir[t:nobs]) for t in range(10)]
 return acovfexpl

def acovf_explicit ( ar , ma , nobs ) : ir = arma_impulse_response ( ar , ma ) acovfexpl = [ np . dot ( ir [ : ( nobs - t ) ] , ir [ t : nobs ] ) for t in range ( 10 ) ] return acovfexpl
add correlation of ma representation explicitely .