docs: def _get_experiments(self):
          """Get all experiments from the hdf5 file"""
          explist = []
          with h5py.File(name=self.path, mode="r") as h5:
              if "Experiments" not in h5:
                  msg = "Group 'Experiments' not found in {}.".format(self.path)
                  raise HyperSpyNoDataFoundError(msg)
              for name in h5["Experiments"]:
                  # check experiment
                  if self._check_experiment(name):
                      explist.append(name)
          explist.sort()
          if not explist:
              # if this error is raised, the signal_type is probably not
              # set to "hologram".
              msg = "No supported data found: {}".format(self.path)
              raise HyperSpyNoDataFoundError(msg)
          return explist