code: def login!(passwd = nil)
        self.password = passwd || self.password
        response = client.login(username.to_s, password.to_s)
        apply_attributes! response.result
        self.session_token.present?
      end
docs: Login and get a session token for this user.
   @param passwd [String] The password for this user.
   @return [Boolean] True/false if we received a valid session token.