Method fromkeys

crates/vm/src/builtins/dict.rs:272–294

(
        class: PyTypeRef,
        iterable: ArgIterable,
        value: OptionalArg<PyObjectRef>,
        vm: &VirtualMachine,
    )

impl PyDict {
    #[pyclassmethod]
    fn fromkeys(
        class: PyTypeRef,
        iterable: ArgIterable,
        value: OptionalArg<PyObjectRef>,
        vm: &VirtualMachine,
    ) -> PyResult {
        let value = value.unwrap_or_none(vm);
        let d = PyType::call(&class, ().into(), vm)?;
        match d.downcast_exact::<Self>(vm) {
            Ok(pydict) => {
                for key in iterable.iter(vm)? {
                    pydict.__setitem__(key?, value.clone(), vm)?;
                }
                Ok(pydict.into_pyref().into())
            }
            Err(pyobj) => {
                for key in iterable.iter(vm)? {
                    pyobj.set_item(&*key?, value.clone(), vm)?;
                }
                Ok(pyobj)
            }
        }
    }

    pub fn __len__(&self) -> usize {
        self.entries.len()