code: def dirty_fields(self):
          
  
          dirty_fields = []
  
          for field in self.all_fields:
              if field not in self._original:
                  dirty_fields.append(field)
              elif self._original[field] != getattr(self, field):
                  dirty_fields.append(field)
          return dirty_fields
docs: Return an array of field names that are dirty
  
          Dirty means if a model was hydrated first from the
          store & then had field values changed they are now
          considered dirty.
  
          For new models all fields are considered dirty.
  
          :return: list