code: public Collection<PartnerUser> list(long partnerId, long accountId)
      {
          return HTTP.GET(String.format("/v2/partners/%d/accounts/%d/users", partnerId, accountId), PARTNER_USERS).get();
      }
docs: Returns the set of users.
  @param partnerId The id of the partner for the users
  @param accountId The id of the account for the users
  @return The set of users