code: def testHalfCauchyInvalidScale(self):
      invalid_scales = [0.0, -0.01, -2.0]
      loc = self._create_placeholder_with_default(0.0, name="loc")
      for scale_ in invalid_scales:
          scale = self._create_placeholder_with_default(
              scale_, name="scale"
          )
          with self.assertRaisesOpError("Condition x > 0"):
              dist = half_cauchy.HalfCauchy(
                  loc, scale, validate_args=True
              )
              self.evaluate(dist.entropy())
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import half_cauchy
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 8 for calling the _HalfCauchyTest obj's underlying member method code with example usage: obj.testHalfCauchyInvalidScale() without return types