input: 
  def print_star_pattern(lines: int) -> None:
      """
      Print a pattern of stars, first increasing in number and then decreasing, 
      based on the number of lines specified.
      
      >>> print_star_pattern(3)
      *
      **
      ***
      **
      *
      >>> print_star_pattern(5)
      *
      **
      ***
      ****
      *****
      ****
      ***
      **
      *
      """
      for i in range(lines):
          for j in range(i + 1):
              print("*", end="")
          print("")
      for i in range(lines, 0, -1):
          for j in range(i):
              print("*", end="")
          print("")
  
output:     for i in range(lines - 1, 0, -1):
          for j in range(i):
              print("*", end="")
          print("")