code: def delegated_login(self, login, admin_zc, duration=0):
          
          # a duration of zero is interpretted literaly by the API...
          selector = zobjects.Account(name=login).to_selector()
          delegate_args = {'account': selector}
          if duration:
              delegate_args['duration': duration]
          resp = admin_zc.request('DelegateAuth', delegate_args)
  
          lifetime = resp['lifetime']
          authToken = resp['authToken']
  
          self.login_account = login
          self.login_with_authToken(authToken, lifetime)
docs: Use another client to get logged in via delegated_auth mechanism by an
          already logged in admin.
  
          :param admin_zc: An already logged-in admin client
          :type admin_zc: ZimbraAdminClient
          :param login: the user login (or email) you want to log as