XGBoost Hyperparameter Name Typo

A misspelled parameter is silently ignored in an XGBoost configuration.

import xgboost as xgb

model = xgb.XGBClassifier(
    n_estimator=500,     # want 500 boosting rounds
    learning_rate=0.05,
    max_depth=4
)
model.fit(X_train, y_train)

The model trains with far fewer trees than intended. What is the bug?