code: def testModeInvalid(self):
      alpha = np.array([1.0, 2, 3])
      dist = dirichlet.Dirichlet(
          concentration=alpha, allow_nan_stats=False
      )
      with self.assertRaisesOpError("Condition x < y.*"):
          self.evaluate(dist.mode())
  
imports: import numpy
  from scipy import special
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import exp
  from tensorflow_probability.python.distributions import dirichlet
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
  from tensorflow_probability.python.util import deferred_tensor
label_desc: Use image node_id 18 for calling the DirichletTest obj's underlying member method code with example usage: obj.testModeInvalid() without return types