from typing import Tuple


def split_domain(name: str) -> Tuple[str, str]:
    """Split a fully-qualified reStructuredText directive or role name into
    its (domain, name) pair.

    For example, "mongodb:ref" becomes ("mongodb", "ref"), while simply
    "ref" becomes ("", "ref").
    """
    parts = name.split(":", 1)
    if len(parts) == 1:
        return "", parts[0]
    return parts[0], parts[1]