input: Write a function to generate the following output pattern using nested loops. The function should print numbers in ascending order for each row, where the number of rows is controlled by the input parameter `num_rows`.
  
  
  def print_pattern(num_rows):
      for i in range(1, num_rows + 1):
          for j in range(1, i + 1):
              print(j, end="")
          print()
  
  assert print_pattern(3) == None
  # Expected output:
  # 1
  # 12
  # 123
  
  assert print_pattern(5) == None
  # Expected output:
  # 1
  # 12
  # 123
  # 1234
  # 12345
  
  assert print_pattern(1) == None
  # Expected output:
  # 1
  
output: def print_pattern(num_rows):
      for i in range(1, num_rows + 1):
          for j in range(1, i + 1):
              print(j, end="")
          print()