code: private static CheerleaderClient getInstance(Context context, String clientId, String artistName) {
          if (clientId == null) {
              throw new IllegalArgumentException("Sound cloud client id can't be null.");
          }
          if (artistName == null) {
              throw new IllegalArgumentException("Sound cloud artistName can't be null.");
          }
          if (sInstance == null || sInstance.mIsClosed) {
              sInstance = new CheerleaderClient(context.getApplicationContext(), clientId, artistName);
          } else {
              sInstance.mRequestSignatorInterceptor.setClientId(clientId);
              sInstance.mClientKey = clientId;
              sInstance.mArtistName = artistName;
          }
          return sInstance;
      }
docs: Simple Sound cloud client initialized with a client id.
  
  @param context    context used to instantiate internal components, no hard reference will be kept.
  @param clientId   sound cloud client id.
  @param artistName sound cloud artiste name.
  @return instance of {@link CheerleaderClient}