[USER (data scientist)]: Cool, now let's calculate the range for each of those numerical columns. Please generate the code with the output in dictionary type.
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd  
import pickle
from decision_company import read_csv_file, get_min_value, get_max, fetch_column

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

print("ranges:\n", ranges)  

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

---END CODE TEMPLATE---

[YOU (AI assistant)]: You got it! You can use a for loop to iterate through the numerical columns and calculate the range. Here's the code:

# MY SOLUTION BEGIN:
