import multiprocessing
def xl2csv(file):
    temp=pd.read_excel(file)
    print("merging")
    return temp.to_csv(file[:-5]+'.csv',index=False)


p1=multiprocessing.Process(target=xl2csv,args=(r"...1.xlsx",))
p2=multiprocessing.Process(target=xl2csv,args=(r"...2.xlsx",))
p3=multiprocessing.Process(target=xl2csv,args=(r"...3.xlsx",))
p4=multiprocessing.Process(target=xl2csv,args=(r"...4.xlsx",))

p1.start()
p2.start()
p3.start()
p4.start()

p1.join()
p2.join()
p3.join()
p4.join()

I tried the above code and I expect the 4 excel files will be converted to csv, is that i missed some of the parameters. I can perform the above task in a for loop but it is very slow.