code: def test_backprop_conv(self):
      conv = nn.Conv2d(3, 16, 3)
      for p in get_parameters(conv):
          p.shard_((d0, d1))
      optim = nn.optim.Adam(get_parameters(conv))
      fake_image = Tensor.rand((2, 3, 32, 32)).shard((d0, d1), axis=0)
      out = conv(fake_image)
      optim.zero_grad()
      out.mean().backward()
      # for p in get_parameters(conv): p.grad.realize()
      optim.step()
  
imports: import functools
  import unittest
  from tinygrad import Tensor, Device, nn, GlobalCounters
  from tinygrad.device import _BufferCopy
  from tinygrad.helpers import CI
  from tinygrad.jit import TinyJit
  from tinygrad.nn.state import get_parameters
  import numpy
label_desc: Use image node_id 34 for calling the TestMultiTensor obj's underlying member method code with example usage: obj.test_backprop_conv() without return types