def get_block_op_pairs(pairs_str):
    """
        # operators ,such as {} [] ()  ......could be user-defined
        # >>> get_block_op_pairs("{}[]")
        # {1: ('{', '}'), 2: ('[', ']')}
        # >>> get_block_op_pairs("{}[]()")
        # {1: ('{', '}'), 2: ('[', ']'), 3: ('(', ')')}
        # >>> get_block_op_pairs("{}[]()<>")
        # {1: ('{', '}'), 2: ('[', ']'), 3: ('(', ')'), 4: ('<', '>')}
    """
    pairs_str_len = pairs_str.__len__()
    pairs_len = pairs_str_len // 2
    pairs_dict = {}
    for i in range(1, pairs_len + 1):
        pairs_dict[i] = pairs_str[i * 2 - 2], pairs_str[i * 2 - 1]
    return pairs_dict
