code: def lookup(self, label):
          ''' take a field_name_label and return the id'''
          if self.is_child:
              try:
                  return self._children[label]
              except KeyError:
                  self._children[label] = ChildFieldPicklist(self.parent, 
                                                             label, 
                                                             self.field_name) 
                  return self._children[label]
          else:
              return get_label_value(label, self._picklistf lookup(self, label):
          ''' take a field_name_label and return the id'''
          if self.is_child:
              try:
                  return self._children[label]
              except KeyError:
                  self._children[label] = ChildFieldPicklist(self.parent, 
                                                             label, 
                                                             self.field_name) 
                  return self._children[label]
          else:
              return get_label_value(label, self._picklist)
docs: take a field_name_label and return the id