How to use the blockcypher.utils.is_valid_block_representation function in blockcypher

def get_block_overview(block_representation, coin_symbol='btc', txn_limit=None,
        txn_offset=None, api_key=None):
    """
    Takes a block_representation, coin_symbol and txn_limit and gets an overview
    of that block, including up to X transaction ids.
    Note that block_representation may be the block number or block hash
    """

    assert is_valid_coin_symbol(coin_symbol)
    assert is_valid_block_representation(
            block_representation=block_representation,
            coin_symbol=coin_symbol)

    url = make_url(coin_symbol, **dict(blocks=block_representation))

    params = {}
    if api_key:
        params['token'] = api_key
    if txn_limit:
        params['limit'] = txn_limit
    if txn_offset:
        params['txstart'] = txn_offset

    r = requests.get(url, params=params, verify=True, timeout=TIMEOUT_IN_SECONDS)
    response_dict = get_valid_json(r)

def get_blocks_overview(block_representation_list, coin_symbol='btc', txn_limit=None, api_key=None):
    '''
    Batch request version of get_blocks_overview
    '''
    for block_representation in block_representation_list:
        assert is_valid_block_representation(
                block_representation=block_representation,
                coin_symbol=coin_symbol)
    assert is_valid_coin_symbol(coin_symbol)

    blocks = ';'.join([str(x) for x in block_representation_list])
    url = make_url(coin_symbol, **dict(blocks=blocks))

    logger.info(url)

    params = {}
    if api_key:
        params['token'] = api_key
    if txn_limit:
        params['limit'] = txn_limit

    r = requests.get(url, params=params, verify=True, timeout=TIMEOUT_IN_SECONDS)

def get_valid_metadata_identifier(coin_symbol, address, tx_hash, block_hash):
    err_msg = 'Please supply only one of: address, tx_hash, or block_hash'
    assert sum([1 for x in (address, tx_hash, block_hash) if x]) == 1, err_msg

    if address:
        assert is_valid_address_for_coinsymbol(
                b58_address=address,
                coin_symbol=coin_symbol), address
        return dict(addrs=address)
    elif tx_hash:
        assert is_valid_hash(tx_hash), tx_hash
        return dict(txs=tx_hash)

    elif block_hash:
        assert is_valid_block_representation(
                block_representation=block_hash,
                coin_symbol=coin_symbol)
        return dict(blocks=block_hash)
    else:
        raise Exception('Logic Fail: This Should Not Be Possible')