NotImplementedError: mean is not implemented: Categorical

I get the following error

NotImplementedError: mean is not implemented: Categorical

if I execute the following code

import tensorflow_probability as tfp

prob_dist = tfp.distributions.Categorical(probs=[1.0])
print(prob_dist.mean())

I get a similar error, if I attempt to call stddev(). I am using TFP 0.8.0 with TF 2.

The parameters mean and standard deviation are not usually defined for a categorical distribution and this error is due to the fact that tfp.distributions.Categorical inherits from tfp.distributions.Distribution, which defines the mean and stddev methods. PyCharm even suggests the auto-completion of these two methods for the tfp.distributions.Categorical, but this is at least misleading. Maybe tfp.distributions.Categorical should not inherit fromtfp.distributions.Distribution, which should not have those methods in the first place, because not all distributions have a well-defined mean or standard deviation.

Reproduce the provided TensorFlow Probability snippet with tfp.distributions.Categorical, then read the linked Categorical and Distribution API documentation. Determine whether the inherited mean() and stddev() behavior should be changed or documented differently; done means the categorical distribution's interface no longer misleadingly offers unsupported statistics, with corresponding behavior or documentation agreed.