code: def parse_parameters(self, parameters, array_class=None):
          
          # get the type of array class to use
          if array_class is None:
              array_class = FieldArray
          # get the names of fields needed for the given parameters
          possible_fields = self[self.samples_group].keys()
          return array_class.parse_parameters(parameters, possible_fields)
docs: Parses a parameters arg to figure out what fields need to be loaded.
  
          Parameters
          ----------
          parameters : (list of) strings
              The parameter(s) to retrieve. A parameter can be the name of any
              field in ``samples_group``, a virtual field or method of
              ``FieldArray`` (as long as the file contains the necessary fields
              to derive the virtual field or method), and/or a function of
              these.
          array_class : array class, optional
              The type of array to use to parse the parameters. The class must
              have a ``parse_parameters`` method. Default is to use a
              ``FieldArray``.
  
          Returns
          -------
          list :
              A list of strings giving the fields to load from the file.