def METHOD_NAME(self) -> "Serializable":
    copied = type(self)()
    copied_fields = copied._FIELDS
    for k, field in self._FIELDS.items():
        try:
            # Slightly faster than getattr.
            value = field.get(self, k)
            copied_fields[k].set(copied, value)
        except AttributeError:
            continue
    return copied