text: a = "string"
  b = len(a)
  print(b)
  
  print(a[0:0])
  print(a[1:1])
  print(a[2:2])
  print(a[3:3])
  print(a[4:4])
  print(a[5:5])
  # If the first number is equal the second number in a slice. Nothing output.
  
  print(a[:0])
  # print("string"[:0]) output nothing.
  
  print(a[5:])
  # print(a[b - 1:]) will output the last character.
  
  # If the first number in a slice is omitted, it is taken to be the
  # start of the list.
  # If the second number is omitted, it is taken to be the end.
  