関連ワード:  python list of tuples second element    python list of tuples get second element    python list of tuples get all second elements    python list of tuples sort by second element    python sort list of tuples by second element descending    python order list of tuples by second element    python sort list of tuples by second element then first    python group list of tuples by second element    python sort list of tuples by two elements    python sort list of tuples by 2nd element