title: ask for user input again if input is wrong without getting the wrong value in the list
body: <p>Why does <code>elif b!= 0 and b!= 1: print (b)</code> not work?
  the user has to put 1 or 0 in order to determine b. If the user doesn't write 1 or 0, I want the program to ask him again &quot;is player a Computer (0) or a human (1)?&quot; without list_2 appending the initial wrong number.</p>
  <pre><code>list_2 = []
  players = int(input(&quot;number of players: &quot;)) 
     
  for i in range (players):
      a = input(&quot;name of player: &quot;)
      b = int(input (&quot;is player a Computer (0) or a human (1)?&quot;))
  
      if b == 0:
          list_2.append([a] + [True])
        
      elif b == 1:
          list_2.append([a] + [False])
  
      elif b!= 0 and b!= 1:
          print (b)
           
  print (list_2)
  </code></pre>