input: Write a function to determine the divisors of a given number and print them. If the number is negative or zero, print an error message. If the number is positive, print all its divisors.
  assert print_divisors(12)==None
  assert print_divisors(1)==None
  assert print_divisors(0)=='Error: Number must be positive'
  assert print_divisors(-5)=='Error: Number must be positive'
  assert print_divisors(30)==None
output: def print_divisors(n):
      if n <= 0:
          print('Error: Number must be positive')
      else:
          for i in range(1, n + 1):
              if n % i == 0:
                  print(i)