code: def testInvalidConstruction(self):
      with self.assertRaises(Exception):
          yahoofeed.Feed(maxLen=0)
  
imports: import datetime
  from .None import common
  from .None import barfeed_test
  from .None import feed_test
  from pyalgotrade.utils import dt
  from pyalgotrade.barfeed import yahoofeed
  from pyalgotrade.barfeed import csvfeed
  from pyalgotrade import bar
  from pyalgotrade import marketsession
label_desc: Use image node_id 2 for calling the FeedTestCase obj's underlying member method code with example usage: obj.testInvalidConstruction() without return types