def get_block_with_transaction(connection, txid):
    """Get a block containing transaction id `txid`

    Args:
        txid (str): id of transaction to be searched.

    Returns:
        block_id (int): the block id or `None`
    """

    raise NotImplementedError
Get a block containing transaction id `txid`

Args:
txid (str): id of transaction to be searched.

Returns:
block_id (int): the block id or `None`
bigchaindb/backend/query.py