how to close a gzip.GzipFile?

[Sidharth]

GzipFile has a parameter 'fileobj' which you could use.
GzipFile( [filename[, mode[, compresslevel[, fileobj]]]])

For iteratng over the file
how about :
line =  oldfileobj.readline()
while line !="":
   oldmd5.update(line)
   line = oldfileobj.readline()