boto etag hash auto verification

boto-etag.py

import boto
s3 = boto.connect_s3()

bucket = s3.get_bucket('robs-super-bucket')
d = bucket.new_key()

file1 = open('testfile.txt', 'r')
file2 = open('otherfile.txt', 'r')

# build the hash from file1
d.etag = d.compute_md5(file)

# but upload file2... <kaboom!>
d.send_file(file2)

# If you set the etag header before uploading a file to s3 using boto,
# s3 will compute the md5 on their side and reject the upload if the 
# sum on their side does not match the sum that you set prior to upload
# 
# e.g.,
# S3DataError: BotoClientError: ETag from S3 did not match computed MD5

Thanks for this gist. Should line 11 be d.etag = d.compute_md5(file1) though?