input: Write a function to print the following pattern: a triangle of asterisks that grows in size up to 5 rows, and then shrinks back down to 1 row.
  
  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() == None
output: 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("")