code: def forward(self, e: torch.Tensor, g: torch.Tensor = None):
      if g is None:
          return self._eval_forward(e)
      return self._train_forward(e, g)
  
imports: import math
  import torch
  import torch.nn.functional
  from open_alpha_tensor.core.modules.attention import AlphaMultiHeadAttention
label_desc: Use image node_id 4 for calling the PolicyHead obj's underlying member method code with example usage: obj.forward(e, g) and returns: self, self