code: def testInvalidFrequency(self):
      with self.assertRaisesRegexp(Exception, "Invalid frequency.*"):
          quandlfeed.Feed(frequency=bar.Frequency.MINUTE)
  
imports: import os
  import datetime
  import tempfile
  import shutil
  import subprocess
  import six
  from .None import common
  from pyalgotrade.tools import quandl
  from pyalgotrade import bar
  from pyalgotrade.barfeed import quandlfeed
label_desc: Use image node_id 5 for calling the ToolsTestCase obj's underlying member method code with example usage: obj.testInvalidFrequency() without return types