Function returns "NoneType"

[eoins]

def collectData(file,arr,index):
    arr[index, 0] = np.fromfile(file, dtype='uint32', count=1)
    eSize = arr[index, 0] 
    
    arr[index, 1] = np.fromfile(file, dtype='uint32', count=1) 
    chan = arr[index, 1]
    
    arr[index, 2] = np.fromfile(file, dtype='uint32', count=1)
    t = arr[index, 2] 
    
    information = [eSize, chan, t]
    
    return information

x = []
x += collectData(inputFile,data,spot)

Hi, Is there any reason that this function would return "Nonetype". I have tried to add these bit sof information I am pulling from a file (which has worked in the past and is definitely not my problem) but I keep getting that this function is returning "Nonetype" or that "'NoneType' object is not iterable". Any help?