docs: def datasets(self):
          """Method returns a list of dataset paths.
  
          Examples
          --------
          >>> for dataset in h5f.datasets():
                  print(dataset)
          '/dataset1/data1/data'
          '/dataset1/data2/data'
          '/dataset2/data1/data'
          '/dataset2/data2/data'
          """
          HiisiHDF._clear_cache()
          self.visititems(HiisiHDF._is_dataset)
          return HiisiHDF.CACHE['dataset_paths']