I'd be interested in using this the mechanisms defined in this PEP to define rank-generic Tensor types in TensorFlow, which are important in specifying `tf.function` signatures in a Pythonic way, using type annotations (rather than the custom input_signature mechanism we have today - see this issue: https://github.com/tensorflow/tensorflow/issues/31579). Variadic generics are among the last few missing pieces to create an elegant set of type definitions for tensors and shapes. Best, Dan Moldovan Software Engineer, TensorFlow Dev Team