How to store result to dataframe from multiple processes with multiple parameter in python

Question

The original code is as follows:

result_m2 = pd.DataFrame(columns = colnames,index = main_dict.keys())
for r in range(rand):
    for s in [0.5,0.6,0.7,0.8]:
        for n in num:
            for k,t in main_dict.items():
                colname = str(r) + '_' + str(s) + '_' + str(n)
                result_m2.at[k, colname] = func(df=df_new,rand_num=r,nb=n,t=t,target='com',ts=s)

How to store result to dataframe from multiple processes with multiple parameter in python such as follows:

with Pool() as pool:
    L = pool.starmap(func, [(1, 1), (2, 1), (3, 1)])