# import necessary libraries
import pandas as pd

# define your series
ser1 = pd.Series([1, 2, 3, 4, 5])
ser2 = pd.Series([4, 5, 6, 7, 8])

# convert series into sets
set1 = set(ser1)
set2 = set(ser2)

# apply difference() method
result = set1.difference(set2)

# print result
print(*result, sep = '\n')