docs: def get_timestamp(self, cycle=None, dataset_number=None,
                        in_minutes=False, full=True):
          """Returns timestamps (in sec or minutes (if in_minutes==True)).
  
          Args:
              cycle: cycle number (all if None)
              dataset_number: first dataset if None
              in_minutes: return values in minutes instead of seconds if True
              full: valid only for cycle=None (i.e. all cycles), returns the full
                 pandas.Series if True, else a list of pandas.Series
  
          Returns:
              pandas.Series (or list of pandas.Series if cycle=None og full=False)
          """
  
          dataset_number = self._validate_dataset_number(dataset_number)
          if dataset_number is None:
              self._report_empty_dataset()
              return
          cycle_index_header = self.headers_normal.cycle_index_txt
          timestamp_header = self.headers_normal.test_time_txt
  
          v = pd.Series()
          test = self.datasets[dataset_number].dfdata
          if cycle:
              c = test[(test[cycle_index_header] == cycle)]
              if not self.is_empty(c):
                  v = c[timestamp_header]
  
          else:
              if not full:
                  self.logger.debug("getting timestapm for all cycles")
                  v = []
                  no_cycles = np.amax(test[cycle_index_header])
                  for j in range(1, no_cycles + 1):
                      txt = "Cycle  %i:  " % j
                      self.logger.debug(txt)
                      c = test[(test[cycle_index_header] == j)]
                      v.append(c[timestamp_header])
              else:
                  self.logger.debug("returning full timestamp col")
                  v = test[timestamp_header]
                  if in_minutes and v is not None:
                      v /= 60.0
          if in_minutes and v is not None:
              v /= 60.0
          return v