input: Write a function to print the following output pattern:
  
  1
  12
  123
  1234
  12345
  
  def print_pattern():
      for i in range(1,6):
          for j in range(1,i+1):
              print(j, end="")
          print()
  
  assert print_pattern() is None
  assert print_pattern() is None
output: def print_pattern():
      for i in range(1,6):
          for j in range(1,i+1):
              print(j, end="")
          print()