There's support for validating promise types, but I don't see a way to create async validators.

What I'm thinking of is something like this:

const foreignKey = z.string().refine(idExistsAsync, {
  message: "ID not found",
});
foreignKey.parseAsync("1234")

Where idExistsAsync is some function that asynchronously checks some backen

As a user of visions, we'd often debug a typeset through plotting it.

Example:

InferenceRelation(
    cls,
    Complex,
    relationship=lambda s: all(np.imag(s.values) == 0),
    transformer=suppress_warnings(to_float),
    name="complex_without_imaginary_part",
)

Alternatively to introducing a name attribute, we could use the function name of relationship (and