code: def changedSet(self, expand=False, parents=False):
          
          return ValueBase.changedSet(self, expand, parents)
docs: :param bool expand: Whether to expand when entire sub-structures are marked as changed.
                              If True, then sub-structures are expanded and only leaf fields will be included.
                              If False, then a direct translation is made, which may include both leaf and sub-structure fields.
          :param bool parents: If True, include fake entries for parent sub-structures with leaf fields marked as changed.
          :returns: A :py:class:`set` of names of those fields marked as changed.
  
          Return a :py:class:`set` containing the names of all changed fields. ::
  
              A = Value(Type([
                  ('x', 'i'),
                  ('z', ('S', None, [
                      ('a', 'i'),
                      ('b', 'i'),
                  ])),
              ]), {
              })
  
              A.mark('z')
              assert A.changedSet(expand=False) == {'z'}         # only shows fields explicitly marked
              assert A.changedSet(expand=True) == {'z.a', 'z.b'} # actually used during network transmission
              A.mark('z.a') # redundant
              assert A.changedSet(expand=False) == {'z', 'z.a'}
              assert A.changedSet(expand=True) == {'z.a', 'z.b'}
              A.unmark('z')
              assert A.changedSet(expand=False) == {'z.a'}
              assert A.changedSet(expand=True) == {'z.a'}
              assert A.changedSet(expand=False, parents=True) == {'z', 'z.a'}
              assert A.changedSet(expand=True, parents=True) == {'z', 'z.a'}
  
  
          * expand=False, parents=False gives a direct mapping of the underlying BitSet as it would (get/monitor),
            or have been (put/rpc), moved over the network.
          * expand=True, parents=False gives the effective set of leaf fields which will be moved over the network.
            taking into account the use of whole sub-structure compress/shorthand bits.
          * expand=False, parents=True gives a way of testing if anything changed within a set of interesting fields
            (cf. set.intersect).