code: def update(self, dict):
          
          for field in self.sorted_fields():
              if field in dict:
                  if dict[field] is None:
                      delattr(self, field)
                  else:
                      setattr(self, field, dict[field])
docs: Set all field values from a dictionary.
  
          For any key in `dict` that is also a field to store tags the
          method retrieves the corresponding value from `dict` and updates
          the `MediaFile`. If a key has the value `None`, the
          corresponding property is deleted from the `MediaFile`.