+ def editors(self):
+ """Returns a set of all editors for book and its children.
+
+ :returns: set of dcparser.Person objects
+ """
+ if self.book_info is None:
+ raise NoDublinCore('No Dublin Core in document.')
+ persons = set(self.book_info.editors +
+ self.book_info.technical_editors)
+ for child in self.parts():
+ persons.update(child.editors())
+ if None in persons:
+ persons.remove(None)
+ return persons
+