The gzip module provides a class, GzipFile, that can be used to read and write files compatible with the GNU gzip program. GzipFile objects work like ordinary files except that data is automatically compressed or decompressed.
GzipFile([filename [, mode [, compresslevel [, fileobj]]]])
Opens a GzipFile. filename is the name of a file, and mode is one of 'r', 'rb', 'a', 'ab', 'w', or 'wb'. The default is 'rb'. compresslevel is an integer from 1 to 9 that controls the level of compression. 1 is the fastest and produces the least compression; 9 is the slowest and produces the most compression (the default). fileobj is an existing file object that should be used. If supplied, it’s used instead of the file named by filename.