def test_from_halflife(self, type_, halflife):
from_hl = EWMA.from_halflife(
inputs=[USEquityPricing.close],
window_length=20,
halflife=halflife,
)
implied_hl = self.decay_rate_to_halflife(from_hl.params['decay_rate'])
assert_almost_equal(halflife, implied_hl)
