def add_feature(self, feat_name):
        """
        Builds a dictionary of feature name to feature id
        If we are at test time and we don't have the feature
        we return -1.
        """
        # Check if feature exists and if so, return the feature ID. 
        if(self.feature_dict in feat_name):
            return self.feature_dict[feat_name]
        # If 'add_features' is True, add the feature to the feature 
        # dictionary and return the feature ID. Otherwise return -1.
        if not self.add_features:
            return -1
        return self.feature_dict.add(feat_name)
dataset/ETHPy150Open LxMLS/lxmls-toolkit/lxmls/sequences/id_feature.py/IDFeatures.add_feature/swapped operands of `in`