human
Solve the following python programming problem given the following code:
def calendar(self, ctx, data) : 
    now = datetime.datetime.now () 
    self.current_date = now 
    month_delta = datetime.timedelta (31) 
    options = itaglibrary.ICalendarOptions (ctx, { 
        
}) 
    strftime = options.get ('strftime', '%b %d, %Y @ %I:%M %p') 
    width = options.get ('width', 2) 
    prev = options.get ('prev', None) 
    next = options.get ('next', None) 
    base = options.get ('base_url', None) 
    calendar_class = options.get ('calendar_class', 'calendar') 
    if (data is None) : 
        d = now 
        current = (d.year, d.month) 
else : 
        if isinstance (data, tuple) : 
            (year, month) = data 
            d = datetime.date (year, month, 4) 
            current = data 
else : 
            if isinstance (data, (datetime.date, datetime.datetime)) : 
                d = data 
                current = (d.year, d.month) 
if ((prev is None) or (next is None)) : 
        p = (d - month_delta) 
        n = (d + month_delta) 
        prev = (p.year, p.month) 
        next = (n.year, n.month) 
        if (base is None) : 
            u = url.URL.fromContext (ctx) 
            segments = u.pathList () 
            if (segments [(- 1)] == '') : 
                u = u.up () 
                segments = segments [: (- 1)] 
if (segments [(- 1)].isdigit () and segments [(- 2)].isdigit ()) : 
                u = u.up ().up () 
prev_url = u 
            next_url = u 
else : 
            prev_url = base 
            next_url = base 
add_query_params = False 
        def buildUrl(u, el) : 
            if add_query_params : 
                (param_name, param_value) = el 
                u = u.add (param_name, str (param_value)) 
else : 
                u = u.child (str (el)) 
return u 
for el in prev : 
            if (el == '?') : 
                add_query_params = True 
                continue 
prev_url = buildUrl (prev_url, el) 
add_query_params = False 
        for el in next : 
            if (el == '?') : 
                add_query_params = True 
               ...

    
    

    Fix the buggy line: return t.table (class_ = calendar_class) [(t.thead [(t.tr [t.th (colspan = '7') [(t.a (href = prev_url) [t.xml ('&larr;')], t.xml (' '), t.xml ('-'.join ([str (el) for el in current])), t.xml (' '), t.a (href = next_url) [t.xml ('&rarr;')])]], [t.tr [[t.td [dayname] for dayname in calendar.weekheader (width).split ()]]])], t.tbody [t.invisible (data = self.days (* current), render = rend.sequence) [t.tr (pattern = 'item', render = rend.sequence) [t.td (pattern = 'item', render = self.render_calendarDay)]]], t.tfoot [t.tr [t.td (colspan = '7') [now.strftime (buildUrl)]]])]
assistant
#Here is Python program to fix the buggy line: return t.

return t.table (class_ = calendar_class) [(t.thead [(t.tr [t.th (colspan = '7') [(t.a (href = prev_url) [t.xml ('&larr;')], t.xml (' '), t.xml ('-'.join ([str (el) for el in current])), t.xml (' '), t.a (href = next_url) [t.xml ('&rarr;')])]], [t.tr [[t.td [dayname] for dayname in calendar.weekheader (width).split ()]]])], t.tbody [t.invisible (data = self.days (* current), render = rend.sequence) [t.tr (pattern = 'item', render = rend.sequence) [t.td (pattern = 'item', render = self.render_calendarDay)]]], t.tfoot [t.tr [t.td (colspan = '7') [now.strftime (strftime)]]])]