I am trying to find out the indices that have null values for Age in my test data and I am using pandas to read in my data

In the test.csv file, the ages are not whole integers like they are in the train.csv file

Ex.: test.csv age '23.5'   or '67.0' while train.csv has '23' or '67'

When I run the following line:

test_data.isnull(test_data.Age).astype(int)

I get the error: TypeError: isnull() takes exactly 1 argument (2 given)

I do NOT get this error when I run the same line with my training data.

I couldn't figure out why, any thoughts?

Thanks

Question on the extra credit: How are we supposed to use the test set on the model if the test set does not include information on whether the test examples survived or not?