code: def input_prototype(self):
      return torch.randn(1, self.input_dim)
  
imports: import logging
  from typing import List
  import torch
  import torch.nn
  import torch.nn.functional
  from reagent.models.base import ModelBase
  from reagent.models.fully_connected_network import ACTIVATION_MAP, gaussian_fill_w_gain, SlateBatchNorm1d
  from torch.distributions import Normal
label_desc: Use image node_id 2 for calling the FullyConnectedProbabilisticNetwork obj's underlying member method code with example usage: obj.input_prototype() and returns: torch