Function casper_contract::contract_api::storage::create_contract_user_group

pub fn create_contract_user_group(
    contract_package_hash: ContractPackageHash, 
    group_label: &str, 
    num_new_urefs: u8, 
    existing_urefs: BTreeSet<URef>
) -> Result<Vec<URef>, ApiError>

Create a new “user group” for a (versioned) contract. User groups associate a set of URefs with a label. Entry points on a contract can be given a list of labels they accept and the runtime will check that a URef from at least one of the allowed groups is present in the caller’s context before execution. This allows access control for entry_points of a contract. This function returns the list of new URefs created for the group (the list will contain num_new_urefs elements).