PEP-593 added typing.Annotated as a way of adding context-specific metadata to
existing types, and specifies that Annotated[T, x] should be treated as T by
any tool or library without special logic for x.

This package provides metadata objects which can be used to represent common
constraints such as upper and lower bounds on scalar values and collection
sizes, a Predicate marker for runtime checks, and descriptions of how we intend
these metadata to be interpreted. In some cases, we also note alternative
representations which do not require this package.