Ellipsis Literal

The ellipsis literal ... is a placeholder for unimplemented code:

# In interfaces and abstract methods
interface IDrawable:
    def draw(self) -> None:
        ...  # Abstract method

# As placeholder for implementation
def todo_function():
    ...  # Placeholder for implementation

Parentheses are grouping and are transparent here as everywhere else: (...) — and any number of nested parentheses — is the same stub body as ..., in a class body, an interface body, and an abstract method, property or event stub. Note this is a stub body on its own line; the one-line form is written def draw(self) -> None: ....

A type position is not a stub: ... inside a type argument (e.g. tuple[int, ...], the Python typing spelling for a runtime-arity tuple) is SPY0149, not this stub form — see #1870. Only the value/stub-body spellings above are accepted.

t: tuple[int, ...] = (1, 2, 3)

Implementation - 🔄 Lowered - No-op for abstract methods or interface methods without a default implementation, otherwise throw new NotImplementedException().