I need to define a function that reads csv files, and after that i need to do some functions that takes the information from thees chosen files and does some calculations, that later is written to a new file.
This is how part of the code looks:

```
if str1 == 'small':
    with open('small.csv', 'r+') as small:
        read_small = csv.reader(small)
        for row in read_small:
            print row
elif str1 == 'big':
    with open('big.csv', 'r+') as big:
            read_big = csv.reader(big)
            for row in read_big:
                print row    
else:
    print "File not found"

```

Now, it prints out the files as i want them to look, but when i try to def a function that does not print out the file, just returns it for me so i can call it in other functions for calculations it does not work! 
Any tips?
(I have googled as \*\*\*\* to find a solution, and i am a newbie)