'Returns field\'s value prepared for saving into a database.'

def get_db_prep_save(self, value, connection=None):

    if (value is not None):
        if (value.tzinfo is None):
            value = default_tz.localize(value)
        else:
            value = value.astimezone(default_tz)
    return super(LocalizedDateTimeField, self).get_db_prep_save(value, connection=connection)
