Prints a 2D list of the possible rolls of two dice in python -

i trying print 2d list of possible rolls of 2 dice in python 3.0+, using eclipse have 2 questions. first, why prof gave function take no arguments, should write main program? second, when runs r.append(result) , said attributeerror: 'int' object has no attribute 'append' can helps me please, thank functions:

def roll_two_dice(): """ ------------------------------------------------------- prints 2d list of possible rolls of 2 dice. ------------------------------------------------------- postconditions:     prints     table of possible dice rolls ------------------------------------------------------- """ r = [] rolls = [] r in range(dice1):     c in range(dice2):         result = r + c + 1         r.append(result)     rolls.append(r)     r = [] print("{}".format(rolls))   main program  functions import roll_two_dice  roll_two_dice() 

the result should

table of 2 dice rolls

  [[2    3    4    5    6    7]  ............. [7    8    9   10   11   12]]   

i not going homework, answer questions:

1) because professor wanted make assignment more challenging

2) because when trying append r, r int

for r in range(dice1):  # r integers in range of 1st die     c in range(dice2):         result = r + c + 1         r.append(result)  # trying append result said integer 

think how name , rename variables change types throughout script.