code: public Team inviteTeamMember(String idOrEmail) throws HelloSignException {
          String key = (idOrEmail != null && idOrEmail.contains("@")) ? Account.ACCOUNT_EMAIL_ADDRESS
                  : Account.ACCOUNT_ID;
          return new Team(
                  httpClient.withAuth(auth).withPostField(key, idOrEmail).post(BASE_URI + TEAM_ADD_MEMBER_URI).asJson());
      }
docs: Adds the user to the current user's team.
  
  @param idOrEmail String new team member's account ID or email address
  @return Team
  @throws HelloSignException thrown if there's a problem processing the
  HTTP request or the JSON response.