code: def testNoModifyArgsList(self):
      x = tf.ones(3, tf.float32)
      y = tf.zeros(4, tf.float32)
      lst = [x, y]
      self.assertEqual(tf.float32, dtype_util.common_dtype(lst))
      self.assertLen(lst, 2)
  
imports: import dataclasses
  from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import dtype_util
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 2 for calling the DtypeUtilTest obj's underlying member method code with example usage: obj.testNoModifyArgsList() without return types