class_docstr: This is a thin wrapper for head execution, which records the output of
  wrapped module for executing the heads forked from this module.
code: def forward(self, input):
      if hasattr(self, "_is_output_stateless"):
          if self._is_output_stateless:
              return self._module(input)
  
      output = self._module(input)
      self.output = output
      return output
  
file_path: ClassyVision/classy_vision/models/classy_block.py
imports: import os
  import torch
  import torch.nn
label_desc: Use image node_id 3 for calling the ClassyBlock obj's underlying member method code with example usage: obj.forward(input) and returns: output, self