#21146: give a more efficient recipe in gzip docs

1 files changed, 2 insertions, 1 deletions

diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
index a8e77049d3..04c41d585c 100644
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -189,9 +189,10 @@ Example of how to create a compressed GZIP file::
 Example of how to GZIP compress an existing file::
 
    import gzip
+   import shutil
    with open('/home/joe/file.txt', 'rb') as f_in:
        with gzip.open('/home/joe/file.txt.gz', 'wb') as f_out:
-           f_out.writelines(f_in)
+           shutil.copyfileobj(f_in, f_out)
 
 Example of how to GZIP compress a binary string::