Function pallet_roles::child::take_or_else

pub fn take_or_else<T, F>(
    child_info: &ChildInfo,
    key: &[u8],
    default_value: F
) -> Twhere
    T: Codec,
    F: FnOnce() -> T,

Return the value of the item in storage under key, or default_value() if there is no explicit entry. Ensure there is no explicit entry on return.