NRRD File of brain tumor is not being read into python with pynrrd module

Question

I have nrrd files of the brain tumor. When reading the file into an array with a header and passing the code print(filename), I get an array of zeros. I checked with NumPy.sum(filename) function and it also gives 0 . does this mean there is something wrong with the file? Also to note that I can see the tumor on 3d slicer. Plz, help. Will really be grateful.