input: Write a function to print the following pattern: a triangle of asterisks that gradually increases in size up to 5 levels, and then decreases back down to 1 level.
  def print_pattern(): 
      for i in range(5):
          for j in range(i+1):
              print("*", end="")
          print("")
  
      for i in range(5, 0, -1):
          for j in range(i):
              print("*", end="")
          print("")
  
  assert print_pattern()
  assert print_pattern()
  assert print_pattern()
  assert print_pattern()
output: def print_pattern(): 
      for i in range(5):
          for j in range(i+1):
              print("*", end="")
          print("")
  
      for i in range(4, 0, -1):
          for j in range(i):
              print("*", end="")
          print("")