docs: def _collapse_pc(master, current, dsn, pc):
      """
      Collapse the paleo or chron for the current time series entry
  
      :param dict master: LiPD data (so far)
      :param dict current: Current time series entry
      :param str dsn: Dataset name
      :param str pc: paleoData or chronData
      :return dict master:
      """
      logger_ts.info("enter collapse_paleo")
      _table_name, _variable_name = _get_current_names(current, dsn, pc)
  
      try:
          # Get the names we need to build the hierarchy
          _m = re.match(re_sheet_w_number, _table_name)
  
          # Is this a summary table or a measurement table?
          _switch = {"meas": "measurementTable", "summ": "summaryTable", "ens": "ensembleTable"}
          _ms = _switch[current["tableType"]]
  
          # This is a measurement table. Put it in the correct part of the structure
          # master[datasetname][chronData][chron0][measurementTable][chron0measurement0]
          if _ms == "measurementTable":
  
              # master[dsn] = _collapse_build_skeleton(master(dsn), _ms, _m)
  
              # Collapse the keys in the table root if a table does not yet exist
              if _table_name not in master[dsn][pc][_m.group(1)][_ms]:
                  _tmp_table = _collapse_table_root(current, dsn, pc)
                  master[dsn][pc][_m.group(1)][_ms][_table_name] = _tmp_table
  
              # Collapse the keys at the column level, and return the column data
              _tmp_column = _collapse_column(current, pc)
              # Create the column entry in the table
              master[dsn][pc][_m.group(1)][_ms][_table_name]['columns'][_variable_name] = _tmp_column
  
          # This is a summary table. Put it in the correct part of the structure
          # master[datasetname][chronData][chron0][model][chron0model0][summaryTable][chron0model0summary0]
          elif _ms in ["ensembleTable", "summaryTable"]:
              # Collapse the keys in the table root if a table does not yet exist
              if _table_name not in master[dsn][pc][_m.group(1)]["model"][_m.group(1) + _m.group(2)][_ms]:
                  _tmp_table = _collapse_table_root(current, dsn, pc)
                  master[dsn][pc][_m.group(1)]["model"][_m.group(1) + _m.group(2)][_ms][_table_name] = _tmp_table
  
              # Collapse the keys at the column level, and return the column data
              _tmp_column = _collapse_column(current, pc)
              # Create the column entry in the table
              master[dsn][pc][_m.group(1)]["model"][_m.group(1) + _m.group(2)][_ms][_table_name]["columns"][_variable_name] = _tmp_column
  
      except Exception as e:
          print("Error: Unable to collapse column data: {}, {}".format(dsn, e))
          logger_ts.error("collapse_paleo: {}, {}, {}".format(dsn, _variable_name, e))
  
      # If these sections had any items added to them, then add them to the column master.
  
      return master