docs: def get_internal_data(self):
          """
          Get data that is saved in pickle/hickle
          """
          if self.filetype is "pickle":
              return pickle.load(open(self.location_internal, "rb"))
          elif self.filetype is "hickle":
              import hickle
              return hickle.load(open(self.location_internal, "rb"))
          else:
              raise ValueError(
                  "Invalue filetype {} (must be {} or {})".format(
                      self.filetype, "pickle", "hickle"
                  )
              )