code: public Optional<PartnerAccount> create(long partnerId, PartnerAccount account)
      {
          return HTTP.POST(String.format("/v2/partners/%d/accounts", partnerId), account, PARTNER_ACCOUNT);
      }
docs: Creates the given account.
  @param partnerId The id of the partner the account belongs to
  @param account The account to create
  @return The account that was created