Decode BSON data to multiple documents as a generator.

    Works similarly to the decode_all function, but yields one document at a
    time.

    `data` must be a string of concatenated, valid, BSON-encoded
    documents.

    :Parameters:
      - `data`: 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

def decode_iter(data, codec_options=DEFAULT_CODEC_OPTIONS):
    """Decode BSON data to multiple documents as a generator.

    Works similarly to the decode_all function, but yields one document at a
    time.

    `data` must be a string of concatenated, valid, BSON-encoded
    documents.

    :Parameters:
      - `data`: 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
    """
    if not isinstance(codec_options, CodecOptions):
        raise _CODEC_OPTIONS_TYPE_ERROR

    position = 0
    end = len(data) - 1
    while position < end:
        obj_size = _UNPACK_INT(data[position:position + 4])[0]
        elements = data[position:position + obj_size]
        position += obj_size

        yield _bson_to_dict(elements, codec_options)