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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 decode_file_iter(file_obj, codec_options=DEFAULT_CODEC_OPTIONS):
 """Decode bson data from a file to multiple documents as a generator. Works similarly to the decode_all function, but reads from the file object in chunks and parses bson in chunks, yielding one document at a time. :Parameters: - `file_obj`: A file object containing BSON data. - `codec_options` (optional):
 An instance of :class:`~bson.codec_options.CodecOptions`. .. versionchanged:: 3.0 Replaced `as_class`, `tz_aware`, and `uuid_subtype` options with `codec_options`. .. versionadded:: 2.8 """

    while True:
        # Read size of next object.
        size_data = file_obj.read(4)
        if len(size_data) == 0:
            break  # Finished with file normaly.
        elif len(size_data) != 4:
            raise InvalidBSON("cut off in middle of objsize")
        obj_size = _UNPACK_INT(size_data)[0] - 4
        elements = size_data + file_obj.read(obj_size)
        yield _bson_to_dict(elements, codec_options)