Code generated from XGBoost model includes "None"

When transpiling XGBRegressor and XGBClassifier models such as the following basic example:

from xgboost import XGBRegressor
from sklearn import datasets
import m2cgen as m2c

iris_data = datasets.load_iris(return_X_y=True)

mod = XGBRegressor(booster="gblinear", max_depth=2)
X, y = iris_data
mod.fit(X[:120], y[:120])

code = m2c.export_to_c(mod)

print(code)

the resulting c-code includes a Pythonesque None :

double score(double * input) {
    return (None) + (((((-0.391196) + ((input[0]) * (-0.0196191))) + ((input[1]) * (-0.11313))) + ((input[2]) * (0.137024))) + ((input[3]) * (0.645197)));
}

Probably I am missing some basic step?

[izeigerman]

@robinvanemden the issue has been fixed in version 0.7.0. Please feel free to reopen this issue if you notice it again.

[StrikerRUS]

OK, they suggest using get_params() method to get actual values of parameters. Refer to https://github.com/dmlc/xgboost/blob/cfae247231e4977a78b255810565369c934fe1b5/tests/python/test_with_sklearn.py#L535-L537 I’ve created a PR with updates: #185.