docs: def returnValue(self, key, last=False):
          '''Return the key's value for the first entry in the current list.
          If 'last=True', then the last entry is referenced."
  
          Returns None is the list is empty or the key is missing.
  
          Example of use:
  
          >>> test = [
          ...    {"name": "Jim",   "age": 18, "income": 93000, "order": 2},
          ...    {"name": "Larry", "age": 18,                  "order": 3},
          ...    {"name": "Joe",   "age": 20, "income": 15000, "order": 1},
          ...    {"name": "Bill",  "age": 19, "income": 29000, "order": 4},
          ... ]
          >>> print PLOD(test).returnValue("name")
          Jim
          >>> print PLOD(test).sort("name").returnValue("name", last=True)
          Larry
          >>> print PLOD(test).sort("name").returnValue("income", last=True)
          None
  
          :param last:
             If True, the last entry is used rather than the first.
          :return:
             A value, or None if the list is empty or the key is missing.
          '''
          row = self.returnOneEntry(last=last)
          if not row:
              return None
          dict_row = internal.convert_to_dict(row)
          return dict_row.get(key, None)