obtain.py

import subprocess
import shelve

def _find_author(filename, lineno):
    prop = subprocess.check_output(f"git blame -pL {lineno},{lineno} {filename}", shell = True)
    lines = prop.decode().split("\n")
    commit = lines[0].split()[0]
    author = lines[1].split()[1]
    return commit, author

def find_author(line):
    prop = subprocess.check_output(f"fgrep -rni {line!r}", shell = True)
    filename, lineno, line = prop.decode().split("\n")[0].split(":")
    return line, _find_author(filename, lineno)

with open("../last.txt") as f:
    lines = f.read().split("\n")

with shelve.open('result.db') as db, shelve.open('fails.db') as fdb:    
    for line in lines:
        if line in db:
            print("continue", line)
            continue
        elif line in fdb:
            print("failed continue", line)
            continue

        try:
            line, answer = find_author(line)
            db[line] = answer
            print(f"added {len(db)}/{5000 - len(fdb)}", line, *answer)
        except Exception as exc:
            fdb[line] = True
            print("failed", line)