code: def load(self, field_xso):
          
          if field_xso.desc:
              self._desc = field_xso.desc
  
          if field_xso.label:
              self._label = field_xso.label
  
          self._required = field_xso.required
docs: Load the field information from a data field.
  
          :param field_xso: XSO describing the field.
          :type field_xso: :class:`~.Field`
  
          This loads the current value, description, label and possibly options
          from the `field_xso`, shadowing the information from the declaration of
          the field on the class.
  
          This method is must be overriden and is thus marked abstract. However,
          when called from a subclass, it loads the :attr:`desc`, :attr:`label`
          and :attr:`required` from the given `field_xso`. Subclasses are
          supposed to implement a mechansim to load options and/or values from
          the `field_xso` and then call this implementation through
          :func:`super`.