Interface to sending email messages to all admins via the amil API.
This class is used to programmatically build an admin email message to send
via the Mail API. The usage is to construct an instance, populate its fields
and call Send().
Unlike the normal email message, addresses in the recipient fields are
ignored and not used for sending.
Example Usage:
An AdminEmailMessage can be built completely by the constructor.
AdminEmailMessage(sender='sender@nowhere.com',
subject='a subject',
body='This is an email to you').Send()
It might be desirable for an application to build an admin email in
different places throughout the code. For this, AdminEmailMessage is
mutable.
message = AdminEmailMessage()
message.sender = 'sender@nowhere.com'
message.subject = 'a subject'
message.body = 'This is an email to you')
message.check_initialized()
message.send()