phone number, to letters conversion

[hobbyprogrammer]

Hi,
This is a program I wrote this morning, to play around with nested loops,
and error handling routines.

It will convert any 7 digit phone number into all the 2000 plus letter
combinations that make up the letters on the modern phone dial.

import os

import os
class klass:
    "docstring"
    def_int-self:
       self.attribute="var"
       if len (self.attribute)<2:
           pass


#python program code starts here!

print("")
tuple0=("","","")
tuple1=("","","")
tuple2=("a","b","c")
tuple3=("d","e","f")
tuple4=("g","h","i")
tuple5=("j","k","l")
tuple6=("m","n","o")
tuple7=("p","q","r","s")
tuple8=("t","u","v")
tuple9=("w","x","y","z")
print("");print("");print("This program will return all the letter conbinations")
print(                          "that are available on the modern phone")
print("You just type in a seven digit number and let the program display")
print("all the letter conbinations that make up that number  Enjoy");print("")

flg=0
quit=0
while quit==0:
    list_numbers=[]
    list_tuple=[] 
    cont=0
    while cont==0:
        print("")
        print ("            Enter (0) to exit out of the program");print ("")
        try:
            phone_number=input("Enter a 7 digit phone number (NO spaces)>>   ")
            dummy=int(phone_number) 
            if (phone_number)=="0":
                flg=1
                break
            elif len(phone_number)< 7:
                print("")
                print ("Do not enter less than (7) digits")
            elif len(phone_number)>7:
                print("")
                print ("Do not enter more than (7) digits")
            else:
                cont=1
             
        except:
            print("")
            print ("Enter numbers only no letters or special characters") 
    for number in (phone_number):
        print (number)
        list_numbers.append(number)
    if flg==1:
        break
    print("")
    print (list_numbers)
    for number in (list_numbers):
        if number =="0":
            list_tuple.append(tuple0)
        if number=="1":
            list_tuple.append(tuple1)
        if number=="2":
            list_tuple.append(tuple2)
        if number=="3":
            list_tuple.append(tuple3)
        if number=="4":
            list_tuple.append(tuple4)
        if number=="5":
            list_tuple.append(tuple5)
        if number=="6":
            list_tuple.append(tuple6)
        if number=="7":
            list_tuple.append(tuple7)
        if number=="8":
            list_tuple.append(tuple8)
        if number=="9":
            list_tuple.append(tuple9)
    print("")
    print(list_tuple)
    print("")

    print("")
    a=(list_tuple[0])
    print (a)
    b=(list_tuple[1])
    print(b)
    c=(list_tuple[2])
    print (c)
    d=(list_tuple[3])
    print(d)
    e=(list_tuple[4])
    print(e)
    f=(list_tuple[5])
    print (f)
    g=(list_tuple[6])
    print (g)
    print("")
    n=1
    for A in (a):
        for B in (b):
            for C in (c):
                for D in (d):
                    for E in (e):
                        for F in (f):
                            for G in (g):
                                print ("(",(n),")  ",(A)+(B)+(C)+(D)+(E)+(F)+(G))
                                print("")
                                n=n+1