data_pair: types.Sequence[types.Union[types.Sequence, opts.MapItem, dict]]

This is a type hint for a variable called `data_pair`. It is a sequence (i.e. a list or tuple) that can contain elements of different types. Specifically, each element can be either a sequence (again, a list or tuple), an `opts.MapItem` object, or a dictionary.

`opts.MapItem` is likely a custom class defined in the codebase that represents a key-value pair. The fact that it is listed as a possible type for an element of `data_pair` suggests that this variable is used for storing collections of key-value pairs, possibly for passing around configuration options or other metadata. The dictionaries in `data_pair` may serve a similar purpose.

Overall, this type hint provides some guidance to developers about how `data_pair` should be structured and what kinds of values it can contain.