Error:
Traceback (most recent call last):
    File "C:/Users/RM/Desktop/win6.py", line 150, in <module>
    for from_,to,digit,name2,min_value,max_value in voltage_envelopes[tla_2]:
    ValueError: need more than 3 values to unpack.

data = list(csv.reader(open(LOAD_GEN_DATAFILE)))
    year = raw_input(" ")
    location=raw_input(" ")
    for row in data:
        year_link, from_,to,digit,name2,tla_2,min_value,max_value,last_bus = row[7:16]
        year_link = year
        tla_2=location
        if year_link not in mydict:
            mydict[year_link]={}
    
        voltage_envelopes=mydict[year_link]
        
        if tla_2 not in voltage_envelopes:
            voltage_envelopes[tla_2]=[]
            
        voltage_envelopes[tla_2].append((from_,to,digit,name2,min_value,max_value))
    
    if year_link in mydict and tla_2 in mydict[year_link]:
         voltage_envelopes=mydict[year_link]
         
         for from_,to,digit,name2,min_value,max_value in voltage_envelopes[tla_2]:
             from_=int(from_)
             to=int(to)
             min_value=float(min_value)
             max_value=float(max_value)
             digit=int(digit)
            
             output = 'From Bus #: {}\tTo Bus #: {}\t Area Station: {}\t VMIN: {} pu\tVMAX: {} pu\t' 
             print(output.format(from_, to,name2, min_value, max_value))
             print("\n")
            
            #_c=psspy.getdefaultchar()
            #_i=psspy.getdefaultint()
            #_f=psspy.getdefaultreal()
            #psspy.two_winding_chng_4(from_,to,'%d'% digit,[_i,_i,_i,_i,_i,_i,_i,_i,_i,_i,_i,_i,_i,_i,_i],[_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f, max_value, min_value,_f,_f,_f],[])
    else:
        exit