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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def extract_feature(self, extractor, force_extraction=False, verbose=0, add_args=None, custom_name=None):
 """ Extracts a feature and stores it in the database Parameters extractor : function, which takes the path of a data point and *args as parameters and returns a feature force_extraction : boolean, if True - will re-extract feature even if a feature with this name already exists in the database, otherwise, will only extract if the feature doesn't exist in the database. default value: False verbose : int, if bigger than 0, will print the current number of the file for which data is being extracted add_args : optional arguments for the extractor (list/dictionary/tuple/whatever). if None, the extractor should take only one input argument - the file path. default value: None custom_name : string, optional name for the feature (it will be stored in the database with the custom_name instead of extractor function name). if None, the extractor function name will be used. default value: None Returns ------- None """

        if self._prepopulated is False:
            raise errors.EmptyDatabase(self.dbpath)
        else:
            return extract_feature_base(self.dbpath, self.path_to_set, self._set_object, extractor, force_extraction,
                                        verbose, add_args, custom_name)