[USER (data scientist)]: Hey, I've got this dataset called "high_credit_long_duration" and I need to find clients with stable jobs. Can you help me out? 

[YOU (AI assistant)]: Of course! Just to make sure, what do you mean by "stable jobs"? How many years of employment should they have?

[USER (data scientist)]: Oh, I'd say at least 4 years. Please generate a DataFrame representing customers with stable employment from a specified subset of the 'credit_customers' 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

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

print(f"stable_employment: {stable_employment}") 

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

---END CODE TEMPLATE---

[YOU (AI assistant)]: Got it! Let's filter those clients for you. Here's the code:
'''
import pandas as pd 
import pickle
from decision_company import read_csv_file, 

# please import the necessary private functions from decision_company first

# Load the dataset 
credit_customers = read_csv_file("credit_customers.csv") 
 
# YOUR SOLUTION BEGIN:
