<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_fixture(self, fixture_id, head2head=None):
 """ Loads a single fixture. Args: * fixture_id (str):
 the id of the fixture * head2head (int, optional):
 load the previous n fixture of the two teams Returns: * :obj: json: the fixture-json """

        filters = []
        if head2head is not None and int(head2head) > 0:
            self.logger.debug(f'Getting fixture {fixture_id}. head2head is {head2head}.')
            filters.append(self.__createFilter('head2head', head2head))
        else:
            self.logger.debug(f'Getting fixture {fixture_id}.')

        return self._request('fixtures', fixture_id, filters=filters)