[USER (data scientist)]: Nice one! What about the average loan duration? Please generate the code with the output in dataframe type.
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd  
import pickle
from decision_company import read_csv_file, fetch_column, avg, locate_mode, visit_by_index

# Load the dataset  
credit_customers = read_csv_file("credit_customers.csv")  
  
# YOUR SOLUTION BEGIN:
<code1>
[GENERATE YOUR CODE]   
</code1>
# YOUR SOLUTION END

print(f"average_loan_duration: {average_loan_duration}")  

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

---END CODE TEMPLATE---

[YOU (AI assistant)]: Sure thing! Here's the code to find the average loan duration for the clients in 'stable_employment':

# MY SOLUTION BEGIN:
