I am trying to send Email using this sample code and these command-line options:
dev_appserver.py --smtp_host=smtp.gmail.com --smtp_port=25 --smtp_user=xxx@g
For anyone looking up this answer in 2018 or later: this workaround is no longer needed. You can now use the command like the original poster wrote it:
dev_appserver.py --smtp_host=smtp.gmail.com --smtp_port=25 --smtp_user=xxx@gmail.com --smtp_password=yyy myapp