The difference between [['column']] and [''column"] Cross Validation(2/10)

test_one[“predicted_price”] = model.predict(test_one[[“accommodates”]])
Screen Link:


My Code:

model.predict(test_one[“accommodates”])
Replace this line with your code


What I expected to happen:


What actually happened: 

Replace this line with the output/error


<!--Enter other details below: -->
I can't make out why they used double brackets[[]] instead of single [].

There are some existing posts which should help answer your question such as my answer here - Why double brackets? is applicable to your question as well.