import pandas as pd
a= pd.read_csv(a_csv_file, usecols=[1])
b= pd.read_csv(b_csv_file, usecols=[1])
a_list = a.values.tolist()
b_list = b.values.tolist()
new_a_list = [f[0] for f in a_list]
new_b_list = [f[0] for f in b_list]
both = list(set(new_a_list ).intersection(set(new_b_list )))