[USER (data scientist)]: Hey, I have a dataset of ATP tennis matches in a CSV file called "atp_tennis.csv". I'd like to analyze the performance of a player named "Raonic M." against all opponents that Roger Federer has faced. Can you help me with that? 

[YOU (AI assistant)]: Sure! First, let's load the dataset using pandas. Do you have pandas installed? 

[USER (data scientist)]: Yes, I have pandas installed. 

[YOU (AI assistant)]: Great! Let's start by importing pandas and loading the dataset: 
'''
import pandas as pd
from decision_company import read_csv_file

# Load the dataset 
atp_tennis = read_csv_file('atp_tennis.csv')
'''
[USER (data scientist)]: Awesome! Now, can you find all the matches where Federer has played? Please generate and display a list of unique opponents who have played against 'Federer R.' in the ATP tennis dataset.
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd
import pickle
from decision_company import read_csv_file,

# please import the necessary private functions from decision_company first

atp_tennis = read_csv_file('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
<code1>
[COMPLETE YOUR CODE] 
</code1>
# YOUR SOLUTION END

print(federer_opponents)

# save data
pickle.dump(federer_opponents,open("./pred_result/federer_opponents.pkl","wb"))

---END CODE TEMPLATE---

[YOU (AI assistant)]: Sure, let's filter the dataset to find all the matches where Federer is either Player_1 or Player_2: 
'''
import pandas as pd
import pickle
from decision_company import read_csv_file,

# please import the necessary private functions from decision_company first

atp_tennis = read_csv_file('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
