code: def test_identity(shape, d):
      ctx = F.ctx()
      # creation
      mat = identity(shape, d)
      # shape
      assert mat.shape == shape
      # val
      len_val = min(shape)
      if d is None:
          val_shape = len_val
      else:
          val_shape = (len_val, d)
      val = torch.ones(val_shape)
      assert torch.allclose(val, mat.val)
  
imports: import unittest
  import warnings
  import backend
  import pytest
  import torch
  from dgl.sparse import diag, from_coo, from_csc, from_csr, from_torch_sparse, identity, to_torch_sparse_coo, to_torch_sparse_csc, to_torch_sparse_csr, val_like
  from .utils import rand_coo, rand_csc, rand_csr, rand_diag, sparse_matrix_to_dense
label_desc: Use image node_id 29 for calling a global function with example usage: test_identity(shape, d) without return types