input: Write a function to print a hollow diamond pattern.
  assert print_hollow_diamond(5) == None
  assert print_hollow_diamond(3) == None
  assert print_hollow_diamond(7) == None
output: def print_hollow_diamond(n):
      if n % 2 == 0 or n < 1:
          return None
  
      for i in range(n):
          for j in range(n):
              if i + j == n // 2 or j - i == n // 2 or i - j == n // 2 or i + j == n // 2 * 3:
                  print("*", end="")
              else:
                  print(" ", end="")
          print()
  
      return None