import sys
import pandas as pd
# input_file = sys.argv[1]
# output_file = sys.argv[2]
input_file = "supplier_data.csv"
output_file = "./output_files/4pandas_value_in_set.csv"

data_frame = pd.read_csv(input_file)

important_dates = ['1/20/14', '1/30/14']
data_frame_value_in_set = data_frame.loc[data_frame['Purchase Date']
    .isin(important_dates), :]

data_frame_value_in_set.to_csv(output_file, index=False)