code: private INDArray getMask() {
          // If no input is provided, no mask is used and null is returned
          if (inputIdx < 0) {
              return null;
          }
  
          final INDArray[] inputMaskArrays = graph.getInputMaskArrays();
          return (inputMaskArrays != null ? inputMaskArrays[inputIdx] : null);
      }
docs: Gets the current mask array from the provided input
  @return The mask or null, if no input was provided