asMembers = (aclName) => (acls[aclName] || []).map((email) => {
    if (hasPrefix(email)) {
      return email;
    }
    let prefix = 'user:';
    if (isDomain(email)) {
      prefix = 'domain:';
    } else if (isGroup(email)) {
      prefix = 'group:';
    } else if (isServiceAccount(email)) {
      prefix = 'serviceAccount:';
    }
    return prefix + email;
  })
@param {!Object} acls
@return {!ee.api.Policy}