code: def changed_bytes(self, other):
          
  
          changes = set()
  
          l.warning("FastMemory.changed_bytes(): This implementation is very slow and only for debug purposes.")
          for addr,v in self._contents.items():
              for i in range(self.width):
                  other_byte = other.load(addr+i, 1)
                  our_byte = v.get_byte(i)
                  if other_byte is our_byte:
                      changes.add(addr+i)
  
          return changes
docs: Gets the set of changed bytes between self and other.