<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def first(self):
 """Attempt to retrieve only the first resource matching this request. :return: Result instance, or `None` if there are no matching resources. """

        self.params['limit'] = 1
        result = self.all()
        return result.items[0] if result.total > 0 else None