code: def marginal(self, dim):
      raise NotImplementedError
  
imports: import torch
  from .._utils import _cast_as_tensor
  from .._utils import _update_parameter
  from .._utils import _cast_as_parameter
  from .._utils import _check_parameter
  from .._utils import _reshape_weights
label_desc: Use image node_id 2 for calling the ConditionalDistribution obj's underlying member method code with example usage: obj.marginal(dim) without return types