human
Solve the following python programming problem given the following code:
def gene_timeline(orgnodes) : 
    events = [] 
    def add_event(node, startdate, enddate = None) : 
        if (not startdate) : 
            return 
ev = { 
            'title' : node.heading, 
            'start' : startdate.strftime (EVENT_DATE_FORMAT), 
} 
        if enddate : 
            ev ['end'] = enddate.strftime (EVENT_DATE_FORMAT) 
events.append (ev) 
for node in orgnodes : 
        add_event (od, node.scheduled.start) 
        add_event (node, node.deadline.start) 
        for date in node.datelist : 
            add_event (node, date.start) 
for od in node.rangelist : 
            add_event (node, od.start, od.end) 
return { 
        'dateTimeFormat' : 'iso8601', 
        'events' : events, 
} 

    
    

    Fix the buggy line: add_event (od, node.scheduled.start)
assistant
#Here is Python program to fix the buggy line: add_event (od, node.

add_event (node, node.scheduled.start)