code: def forward(self, x: torch.Tensor) -> torch.Tensor:
      return F.relu(x)
  
imports: import unittest
  import torch
  import torch.nn.functional
  from nni.common.concrete_trace_utils import concrete_trace
label_desc: Use image node_id 2 for calling the Foo obj's underlying member method code with example usage: obj.forward(x) and returns: F