docs: public ApiResponse authorizeAppUser(String email, String password) {
          validateNonEmptyParam(email, "email");
          validateNonEmptyParam(password,"password");
          assertValidApplicationId();
          loggedInUser = null;
          accessToken = null;
          currentOrganization = null;
          Map<String, Object> formData = new HashMap<String, Object>();
          formData.put("grant_type", "password");
          formData.put("username", email);
          formData.put("password", password);
          ApiResponse response = apiRequest(HttpMethod.POST, formData, null,
                  organizationId, applicationId, "token");
          if (response == null) {
              return response;
          }
          if (!isEmpty(response.getAccessToken()) && (response.getUser() != null)) {
              loggedInUser = response.getUser();
              accessToken = response.getAccessToken();
              currentOrganization = null;
              log.info("Client.authorizeAppUser(): Access token: " + accessToken);
          } else {
              log.info("Client.authorizeAppUser(): Response: " + response);
          }
          return response;
      }