code: def _make_matrix_ds1(nrows):
      """Create a test dataset with matrix elements (of varying size)."""
      return _make_scalar_ds(nrows).map(
          lambda x: array_ops.fill([x, 2], x)
      )
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.util import nest
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import array_ops_stack
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops.ragged import ragged_concat_ops
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 3 for calling a global function with example usage: _make_matrix_ds1(nrows) and returns: _make_scalar_ds