code: def test_two_conv(self):
      class LilModel:
          def __init__(self):
              self.c = Conv2d(12, 32, 3, padding=1, bias=False)
              self.c2 = Conv2d(32, 32, 3, padding=1, bias=False)
  
          def forward(self, x):
              return self.c2(self.c(x)).relu()
  
      lm = LilModel()
      model_step(lm)
  
file_path: tinygrad/test/external/graph_batchnorm.py
imports: import unittest
  from tinygrad.nn.state import get_parameters
  from tinygrad.tensor import Tensor
  from tinygrad.nn import Conv2d, BatchNorm2d, optim
label_desc: Use image node_id 2 for calling the TestBatchnorm obj's underlying member method code with example usage: obj.test_two_conv() and returns: self