code: def testSum(self):
      d = collections.NumPyDeque(10)
  
      for i in xrange(10):
          d.append(i)
      self.assertEqual(d[0:3].sum(), 3)
  
imports: import datetime
  from six.moves import xrange
  from .None import common
  from pyalgotrade import utils
  from pyalgotrade.utils import collections
  from pyalgotrade.utils import dt
label_desc: Use image node_id 5 for calling the NumPyDequeTestCase obj's underlying member method code with example usage: obj.testSum() without return types