Issue #27110: Add smtpd.SMTPChannel to __all__, by Jacek KoƂodziej
diff --git a/Lib/smtpd.py b/Lib/smtpd.py
index 5f3b05e..8103ca9 100755
--- a/Lib/smtpd.py
+++ b/Lib/smtpd.py
@@ -89,7 +89,10 @@
 from warnings import warn
 from email._header_value_parser import get_addr_spec, get_angle_addr
 
-__all__ = ["SMTPServer","DebuggingServer","PureProxy","MailmanProxy"]
+__all__ = [
+    "SMTPChannel", "SMTPServer", "DebuggingServer", "PureProxy",
+    "MailmanProxy",
+]
 
 program = sys.argv[0]
 __version__ = 'Python SMTP proxy version 0.3'