code: def send_invitation(self, invitation, **kwargs):
          # type: (OrganizationInvitationBase) -> bool
          
          return self.email_message(
              invitation.invitee_identifier,
              self.invitation_subject,
              self.invitation_body,
              invitation.invited_by,
              **kwargs
          ).send()
docs: Sends an invitation message for a specific invitation.
  
          This could be overridden to do other things, such as sending a confirmation
          email to the sender.
  
          Args:
              invitation:
  
          Returns: