(Python) len traceback, error in .rstrip

name = input ('Enter file name: ')
if len(name) > 1 :
    name = 'mbox-short.txt'
filename = open(name)

for line in filename :
    if 'From ' in line :
        print(line.rstrip)

    else :
        continue


print(filename)

(1)

I'm practicing the code to filter emails in the document through Cocera. I was lazy to type the file name, so I used the len code that Professor Kosera also used, but for some reason, there is a message that I couldn't find the file or directory due to traceback in the fourth line variable. Why is this problem even though I didn't enter the wrong file name? What am I doing wrong?

(2)

If you don't use .rstrip, you can find and print out words without any problems, but if you put .rstrip, The value has been changed to built-in method rstrip of strip object at 0x03DSEA88 and is being output. Whether you get the price you want. Whether you get it or not, the message <_io.TextIOWrappername='mbox-short.txt'mode='r'encoding='cp1252'> is printed at the end, how do I get rid of these messages and get the value I want to get? What's wrong with this problem?

Please give me some advice.