foo must be an email address
MUST conform to the "addr-spec" production in RFC 2822
Convert the email address to a valid form. Examples of valid email addresses:
Note: addr-spec does not include a provision for a display-name. Use atom:name instead. Examples of invalid email addresses:
- firstname.lastname@example.org (Joe Smith)
- Joe Smith <email@example.com>
Not clear? Disagree?
You might be able to find help in one of these fine resources.