E_ADF_001 — ADF: invalid regression mode

The Augmented Dickey-Fuller test received a regression argument that isn't one of the three supported modes:

Mode	Regressors
"n"	No constant, no trend
"c"	Constant (drift) — default
"ct"	Constant + linear trend

How to fix

Python

result = flox.adf(prices, max_lag=8, regression="c")

Common causes

• Passing a long form like "constant" instead of "c".
• Capitalisation: FLOX expects lowercase letters.