[USER (data scientist)]: Great, that's what I needed! Now, I want to make a list of nominal categorical columns from those variables. Can you help me with that? Please generate the code with the output in list type.
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd  
import pickle

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

print("nominal_categorical_columns:\n", nominal_categorical_columns)    

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

---END CODE TEMPLATE---

[YOU (AI assistant)]: Sure thing! Here's the code to create a list of nominal categorical columns:

# MY SOLUTION BEGIN:
