python 3.x - How does this code work? What tells it to stop printing after the third row? Can someone break it down for me, in the most dumbed down way possible? -

import random  def main():     printmatrix(3) 

i don't understand how code stops after third row

def printmatrix(n):     in range(1, n + 1):         j in range(1, n + 1):             print(random.randint(0, 1), end = " ")          print()  main() 

range(1,n+1) builtin returns [1, 2, 3], iterating on range(1, n+1) same iterating on [1, 2, 3] - each loop body executes 3 times before terminating. inner 1 prints entries horizontally , outer 1 causes inner 1 execute 3 times.