Function ensure_members

pub fn ensure_members<OuterOrigin, AccountId, I>(
    o: OuterOrigin,
    n: MemberCount,
) -> Result<MemberCount, &'static str>
where
    OuterOrigin: Into<Result<RawOrigin<AccountId, I>, OuterOrigin>>,

Ensure that the origin o represents at least n members. Returns Ok or an Err otherwise.