What is StringIO in python used for in reality?

It’s used when you have some API that only takes files, but you need to use a string. For example, to compress a string using the gzip module in Python 2:

import gzip
import StringIO

stringio = StringIO.StringIO()
gzip_file = gzip.GzipFile(fileobj=stringio, mode="w")
gzip_file.write('Hello World')
gzip_file.close()

stringio.getvalue()