<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def rfc_cv(n_estimators, min_samples_split, max_features, data, targets):
 """Random Forest cross validation. This function will instantiate a random forest classifier with parameters n_estimators, min_samples_split, and max_features. Combined with data and targets this will in turn be used to perform cross validation. The result of cross validation is returned. Our goal is to find combinations of n_estimators, min_samples_split, and max_features that minimzes the log loss. """

    estimator = RFC(
        n_estimators=n_estimators,
        min_samples_split=min_samples_split,
        max_features=max_features,
        random_state=2
    )
    cval = cross_val_score(estimator, data, targets,
                           scoring='neg_log_loss', cv=4)
    return cval.mean()