code: protected Authenticated getAuthObjFromFile(final File authFile) {
          if (authFile == null) {
              getLog().debug(AUTH_FILE_NOT_CONFIG);
              return null;
          }
  
          if (!authFile.exists()) {
              getLog().error(AUTH_FILE_NOT_EXIST + authFile.getAbsolutePath());
              return null;
          }
  
          try {
              final Authenticated auth = azureConfigure().authenticate(authFile);
              if (auth != null) {
                  getLog().info(AUTH_WITH_FILE + authFile.getAbsolutePath());
              }
              return auth;
          } catch (Exception e) {
              getLog().error(AUTH_FILE_READ_FAIL + authFile.getAbsolutePath());
              getLog().error(e);
          }
          return null;
      }
docs: Get Authenticated object using file.
  
  @param authFile Authentication file object.
  @return Authenticated object of file is valid; otherwise return null.