# Buggy code
def _process_scrape_response(self, body):
    """
    This function handles the response body of a HTTP tracker,
    parsing the results.
    """
    # parse the retrieved results
    if body is None:
        self.failed(msg="no response body")
        return

    response_dict = bdecode(body)
    if not response_dict:
        self.failed(msg="no valid response")
        return

    response_list = []

    unprocessed_infohash_list = self._infohash_list[:]
    if b"files" in response_dict and isinstance(response_dict[b"files"], dict):
        for infohash in response_dict[b"files"]:
            complete = 0
            incomplete = 0
            if isinstance(response_dict[b"files"][infohash], dict):
                complete = response_dict[b"files"][infohash].get(b"complete", 0)
                incomplete = response_dict[b"files"][infohash].get(b"incomplete", 0)

            # Sow complete as seeders. "complete: number of peers with the entire file, i.e. seeders (integer)"
            #  - https://wiki.theory.org/BitTorrentSpecification#Tracker_.27scrape.27_Convention
            seeders = complete
            leechers = incomplete

            # Store the information in the dictionary
            response_list.append(
                {
                    "infohash": hexlify(infohash),
                    "seeders": seeders,
                    "leechers": leechers,
                }
            )

            # remove this infohash in the infohash list of this session
            if infohash in unprocessed_infohash_list:
                unprocessed_infohash_list.remove(infohash)

    elif b"failure reason" in response_dict:
        self._logger.info(
            "%s Failure as reported by tracker [%s]",
            self,
            repr(response_dict[b"failure reason"]),
        )
        self.failed(msg=repr(response_dict[b"failure reason"]))
        return

    # handle the infohashes with no result (seeders/leechers = 0/0)
    for infohash in unprocessed_infohash_list:
        response_list.append(
            {"infohash": hexlify(infohash), "seeders": 0, "leechers": 0}
        )

    self._is_finished = True
    if self.result_deferred and not self.result_deferred.called:
        self.result_deferred.callback({self.tracker_url: response_list})


# Traceback (RuntimeError)
Traceback (most recent call last):
File "TriblerGUI/event_request_manager.py", line 114, in on_read_data
RuntimeError: [Failure instance: Traceback: <class 'RuntimeError'>: expected value (list, dict, int or string) in bencoded string
site-packages/twisted/internet/base.py:1283:run
site-packages/twisted/internet/base.py:1292:mainLoop
site-packages/twisted/internet/base.py:913:runUntilCurrent
site-packages/twisted/internet/task.py:239:__call__
--- <exception caught here> ---
site-packages/twisted/internet/defer.py:151:maybeDeferred
Tribler/Core/Libtorrent/LibtorrentMgr.py:578:_task_process_alerts
]

# Fixed code
def _process_scrape_response(self, body):
    """
    This function handles the response body of a HTTP tracker,
    parsing the results.
    """
    # parse the retrieved results
    if body is None:
        self.failed(msg="no response body")
        return

    response_dict = bdecode_compat(body)
    if not response_dict:
        self.failed(msg="no valid response")
        return

    response_list = []

    unprocessed_infohash_list = self._infohash_list[:]
    if b"files" in response_dict and isinstance(response_dict[b"files"], dict):
        for infohash in response_dict[b"files"]:
            complete = 0
            incomplete = 0
            if isinstance(response_dict[b"files"][infohash], dict):
                complete = response_dict[b"files"][infohash].get(b"complete", 0)
                incomplete = response_dict[b"files"][infohash].get(b"incomplete", 0)

            # Sow complete as seeders. "complete: number of peers with the entire file, i.e. seeders (integer)"
            #  - https://wiki.theory.org/BitTorrentSpecification#Tracker_.27scrape.27_Convention
            seeders = complete
            leechers = incomplete

            # Store the information in the dictionary
            response_list.append(
                {
                    "infohash": hexlify(infohash),
                    "seeders": seeders,
                    "leechers": leechers,
                }
            )

            # remove this infohash in the infohash list of this session
            if infohash in unprocessed_infohash_list:
                unprocessed_infohash_list.remove(infohash)

    elif b"failure reason" in response_dict:
        self._logger.info(
            "%s Failure as reported by tracker [%s]",
            self,
            repr(response_dict[b"failure reason"]),
        )
        self.failed(msg=repr(response_dict[b"failure reason"]))
        return

    # handle the infohashes with no result (seeders/leechers = 0/0)
    for infohash in unprocessed_infohash_list:
        response_list.append(
            {"infohash": hexlify(infohash), "seeders": 0, "leechers": 0}
        )

    self._is_finished = True
    if self.result_deferred and not self.result_deferred.called:
        self.result_deferred.callback({self.tracker_url: response_list})