def sum(self, start=0, end=None):
        """Returns arr[start] + ... + arr[end]"""
        return super(SumSegmentTree, self).reduce(start, end)
def sum(self, start=0, end=None):
        """Returns arr[start] + ... + arr[end]"""
        return super(SumSegmentTree, self).reduce(start, end)
def sum ( self , start = 0 , end = None ) : return super ( SumSegmentTree , self ) . reduce ( start , end )
Returns arr[start] + ... + arr[end]
Returns arr [ start ] + ... + arr [ end ]