Python convert class list in CSV file via pandas.dataframe

import time
import threading
import datetime
import pandas as pd

class Book():
    def __init__(self,id,name,author,comment,content,isbn,summary,title,topic):
        self.id=id
        self.name=name
        self.author=author
        self.comment=comment
        self.content=content
        self.isbn=isbn
        self.summary=summary
        self.title=title
        self.topic=topic
    
book_list=[]
t1=datetime.datetime.now()

arr=range(1,1000001)
for a in arr:
    book_list.append(Book(a,f'Name_{a}',f'Author_{a}',f'Comment_{a}',f'Content_{a}',f'ISBN_{a}',f'Summary_{a}',f'Title_{a}',f'Topic_{a}'))

print(f'Init time cost {datetime.datetime.now()-t1}')

book_data=[]

t1=datetime.datetime.now()
for bk in book_list:
    dic={
        'Id':bk.id,
        'Name':bk.name,
        'Author':bk.author,
        'Comment':bk.comment,
        'Content':bk.content,
        'ISBN':bk.isbn,
        'Summary':bk.summary,
        'Title':bk.title,
        'Topic':bk.topic
    }
    book_data.append(dic)
print(f'Convert book_data to list with keyvalue items cost:{datetime.datetime.now()-t1}')

excelFile=f'book_data_{datetime.datetime.now().strftime('%Y%m%d%H%M%S%f')}.csv'
t1=datetime.datetime.now()
df=pd.DataFrame(book_data)
df.to_csv(excelFile,encoding='utf-8',index=False)
print(f'Store in csv file cost {datetime.datetime.now()-t1},excel file:{excelFile}')

excelFile=f'book_dic_{datetime.datetime.now().strftime('%Y%m%d%H%M%S%f')}.csv'
t1=datetime.datetime.now()
df=pd.DataFrame([bk.__dict__ for bk in book_list])
df.to_csv(excelFile,encoding='utf-8',index=False)
print(f'Store book_dic_ in csv file cost {datetime.datetime.now()-t1},excel file:{excelFile}')