class_docstr: Common tests for CachedDirectedFunction.
code: def inverse(self, y):
      return self.cache.inverse(y)
  
imports: from absl.testing import parameterized
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import cache_util
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 6 for calling the CacheTestBase obj's underlying member method code with example usage: obj.inverse(y) and returns: self