ValueError: GradientBoosting 'learning_rate' out of range

ValueError: GradientBoosting learning_rate invalid

$ python -c "from sklearn.ensemble import GradientBoostingClassifier; GradientBoostingClassifier(learning_rate=0).fit([[0],[1],[2],[3]],[0,1,1,0])"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ValueError: learning_rate must be > 0

Why this happens

Learning rate cannot be zero.

Fix

Use a small positive float.

Wrong code

from sklearn.ensemble import GradientBoostingClassifier
GradientBoostingClassifier(learning_rate=0)

Fixed code

from sklearn.ensemble import GradientBoostingClassifier
GradientBoostingClassifier(learning_rate=0.1)