Optional[Customizes how the current object is rendered when inspected with loupe package.
See chaijs/loupe - src/types.ts for details on the type definition.
a string as the representation of current object, or other values that will be rendered again by loupe.
Optional[Objects may also define their own [util.inspect.custom](depth, opts, inspect) function,
which util.inspect() will invoke and use the result of when inspecting the object.
Provides methods on objects to customize how the objects are rendered in various inspectors.
Please refer to the documentation of respective member for details.