<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def to_dict(self):

 """Extend Field.to_dict, take the display_international attribute."""

        d = Field.to_dict(self)
        if self.display_international:
            d['display_international'] = self.display_international
        return d