code: def test_dense_types():
      x = matrix()
      assert isinstance(x, DenseTensorVariable)
      assert not isinstance(x, DenseTensorConstant)
  
      x = constant(1)
      assert not isinstance(x, DenseTensorVariable)
      assert isinstance(x, DenseTensorConstant)
  
imports: from copy import copy
  import numpy
  import pytest
  from numpy.testing import assert_array_equal, assert_equal, assert_string_equal
  import pytensor
  import tests.unittest_tools
  from pytensor.compile import DeepCopyOp
  from pytensor.compile.mode import get_default_mode
  from pytensor.graph.basic import Constant, equal_computations
  from pytensor.tensor import get_vector_length
  from pytensor.tensor.basic import constant
  from pytensor.tensor.elemwise import DimShuffle
  from pytensor.tensor.math import dot, eq, matmul
  from pytensor.tensor.shape import Shape
  from pytensor.tensor.subtensor import AdvancedSubtensor, Subtensor, inc_subtensor, set_subtensor
  from pytensor.tensor.type import TensorType, cscalar, dmatrix, dscalar, dvector, iscalar, ivector, matrices, matrix, scalar, tensor3
  from pytensor.tensor.type_other import MakeSlice, NoneConst
  from pytensor.tensor.variable import DenseTensorConstant, DenseTensorVariable, TensorConstant, TensorVariable
  from tests.tensor.utils import random
label_desc: Use image node_id 13 for calling a global function with example usage: test_dense_types() without return types