+ def get_field_names(self):
+ if isinstance(self.key, (list, tuple, set, frozenset)):
+ return set(self.key)
+ else:
+ return set([self.key])
+
+ def get_value_names(self):
+ if isinstance(self.value, (list, tuple, set, frozenset)):
+ return set(self.value)
+ else:
+ return set([self.value])
+
+ def has_empty_value(self):
+ if isinstance(self.value, (list, tuple, set, frozenset)):
+ return not any(self.value)
+ else:
+ return not self.value