old_contents: import torch
  import torch.nn as nn
  
  from metal.modules.base_module import InputModule
  
  class IdentityModule(InputModule):
      """A generic nn.Module class with a method for getting the output dim."""
      def __init__(self):
          super().__init__() 
     
      def get_output_dim(self):
          raise NotImplementedError()
new_contents: import torch
  import torch.nn as nn
  
  from metal.modules.base_module import InputModule
  
  class IdentityModule(InputModule):
      """A default identity input layer that simply passes the input through."""
      def __init__(self, output_dim):
          super().__init__()
          self.output_dim = output_dim
     
      def get_output_dim(self):
          return self.output_dim
subject: Create IdentityModule