code: def kl_divergence(self):
      return sum(
          strategy.kl_divergence().sum()
          for strategy in self.sub_variational_strategies
      )
  
imports: import warnings
  import torch
  from linear_operator.operators import BlockDiagLinearOperator
  from ...None import settings
  from ...distributions import MultitaskMultivariateNormal
  from ...likelihoods import Likelihood
  from ..approximate_gp import ApproximateGP
  from ..gp import GP
label_desc: Use image node_id 3 for calling the _DeepGPVariationalStrategy obj's underlying member method code with example usage: obj.kl_divergence() and returns: sum