bpo-34246: Use no mutable default args in smtplib (GH-8554)
Some methods of the SMTP class use mutable default arguments. Specially
`send_message` is affected as it mutates one of the args by appending items
to it, which has side effects on further calls.
diff --git a/Misc/ACKS b/Misc/ACKS
index 82fbc92..75047d8 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -22,6 +22,7 @@
Anton Afanasyev
Ali Afshar
Nitika Agarwal
+Pablo S. Blum de Aguiar
Jim Ahlstrom
Farhan Ahmad
Matthew Ahrens
diff --git a/Misc/NEWS.d/next/Library/2018-07-29-15-25-15.bpo-34246.xiKq-Q.rst b/Misc/NEWS.d/next/Library/2018-07-29-15-25-15.bpo-34246.xiKq-Q.rst
new file mode 100644
index 0000000..50c91ec
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-07-29-15-25-15.bpo-34246.xiKq-Q.rst
@@ -0,0 +1,2 @@
+:meth:`smtplib.SMTP.send_message` no longer modifies the content of the
+*mail_options* argument. Patch by Pablo S. Blum de Aguiar.