# Buggy code
def OnVerifyFilter(self, widget):
    outfilter = "(\\\\("

    df = list(self.filtersiters.keys())
    df.sort()

    proccessedfilters = []
    failed = {}

    for filter in df:
        iter = self.filtersiters[filter]
        dfilter = self.filterlist.get_value(iter, 0)
        escaped = self.filterlist.get_value(iter, 1)

        if escaped:
            dfilter = re.escape(dfilter)
            dfilter = dfilter.replace("\\*", ".*")

        try:
            re.compile("(" + dfilter + ")")
            outfilter += dfilter
            proccessedfilters.append(dfilter)
        except Exception as e:
            failed[dfilter] = e

        if filter is not df[-1]:
            outfilter += "|"

    outfilter += ")$)"

    try:
        re.compile(outfilter)

    except Exception as e:
        failed[outfilter] = e

    if len(list(failed.keys())) >= 1:
        errors = ""

        for filter, error in list(failed.items()):
            errors += "Filter: %(filter)s Error: %(error)s " % {
                "filter": filter,
                "error": error,
            }

        error = _(
            "%(num)d Failed! %(error)s "
            % {"num": len(list(failed.keys())), "error": errors}
        )

        self.VerifiedLabel.set_markup(
            '<span color="red" weight="bold">%s</span>' % error
        )
    else:
        self.VerifiedLabel.set_markup("<b>Filters Successful</b>")


# Traceback (SystemError)
Thu 07:58 Nicotine+ supports a country code blocker. This requires a (GPL'ed) library called GeoIP. You can find it here: C library:       https://github.com/maxmind/geoip-api-c Python
bindings: https://github.com/maxmind/geoip-api-python (the python bindings require the C library)
Traceback (most recent call last):
File "/usr/local/bin/nicotine", line 255, in <module>
run()
File "/usr/local/bin/nicotine", line 231, in run
app = frame.MainApp(data_dir, config, plugins, trayicon, hidden, bindip, port)
File "/usr/local/lib/python3.7/site-packages/pynicotine/gtkgui/frame.py", line 3595, in __init__
self.frame = NicotineFrame(data_dir, config, plugins, trayicon, start_hidden, bindip, port)
File "/usr/local/lib/python3.7/site-packages/pynicotine/gtkgui/frame.py", line 273, in __init__
config
File "/usr/local/lib/python3.7/site-packages/pynicotine/pynicotine.py", line 130, in __init__
self.shares = Shares(self)
File "/usr/local/lib/python3.7/site-packages/pynicotine/shares.py", line 75, in __init__
self.CompressShares("normal")
File "/usr/local/lib/python3.7/site-packages/pynicotine/shares.py", line 201, in CompressShares
m.makeNetworkMessage(nozlib=0, rebuild=True)
File "/usr/local/lib/python3.7/site-packages/pynicotine/slskmessages.py", line 1709, in makeNetworkMessage
msg = msg + self.packObject(len(list(self.list.keys())))
File "/usr/local/lib/python3.7/_collections_abc.py", line 720, in __iter__
yield from self._mapping
File "/usr/local/lib/python3.7/shelve.py", line 95, in __iter__
for k in self.dict.keys():
SystemError: Negative size passed to PyBytes_FromStringAndSize

# Fixed code
def OnVerifyFilter(self, widget):
    outfilter = "(\\\\("

    df = list(self.filtersiters.keys())
    df.sort()

    proccessedfilters = []
    failed = {}

    for filter in df:
        iter = self.filtersiters[filter]
        dfilter = self.filterlist.get_value(iter, 0)
        escaped = self.filterlist.get_value(iter, 1)

        if escaped:
            dfilter = re.escape(dfilter)
            dfilter = dfilter.replace("\\*", ".*")

        try:
            re.compile("(" + dfilter + ")")
            outfilter += dfilter
            proccessedfilters.append(dfilter)
        except Exception as e:
            failed[dfilter] = e

        if filter is not df[-1]:
            outfilter += "|"

    outfilter += ")$)"

    try:
        re.compile(outfilter)

    except Exception as e:
        failed[outfilter] = e

    if len(failed) >= 1:
        errors = ""

        for filter, error in list(failed.items()):
            errors += "Filter: %(filter)s Error: %(error)s " % {
                "filter": filter,
                "error": error,
            }

        error = _("%(num)d Failed! %(error)s " % {"num": len(failed), "error": errors})

        self.VerifiedLabel.set_markup(
            '<span color="red" weight="bold">%s</span>' % error
        )
    else:
        self.VerifiedLabel.set_markup("<b>Filters Successful</b>")