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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 read(filename, groupname=None, from_item=None, to_item=None, from_time=None, to_time=None, index=None):
 """Reads in a h5features file. :param str filename: Path to a hdf5 file potentially serving as a container for many small files :param str groupname: HDF5 group to read the data from. If None, guess there is one and only one group in `filename`. :param str from_item: Optional. Read the data starting from this item. (defaults to the first stored item) :param str to_item: Optional. Read the data until reaching the item. (defaults to from_item if it was specified and to the last stored item otherwise) :param float from_time: Optional. (defaults to the beginning time in from_item) the specified times are included in the output :param float to_time: Optional. (defaults to the ending time in to_item) the specified times are included in the output :param int index: Not implemented, raise if used. :return: A tuple (times, features) or (times, features, properties) such as: * time is a dictionary of 1D arrays values (keys are items). * features: A dictionary of 2D arrays values (keys are items) with the 'features' dimension along the columns and the 'time' dimension along the lines. * properties: A dictionnary of dictionnaries (keys are items) with the corresponding properties. If there is no properties recorded, this value is not returned. .. note:: Note that all the files that are present on disk between to_item and from_item will be loaded and returned. It's the responsibility of the user to make sure that it will fit into RAM memory. """

    # TODO legacy read from index not implemented
    if index is not None:
        raise NotImplementedError

    reader = Reader(filename, groupname)
    data = (reader.read(from_item, to_item, from_time, to_time)
            if index is None else reader.index_read(index))
    if data.has_properties():
        return data.dict_labels(), data.dict_features(), data.dict_properties()
    else:
        return data.dict_labels(), data.dict_features()