input: from typing import List
  
  def print_number_pattern() -> str:
      """Print a number pattern as described in the instruction.
      The pattern starts from 1 and increases one by one in each row until reaching 5.
      Each row should have numbers from 1 to the current row's number.
  
      Examples:
      >>> print_number_pattern()
      1
      12
      123
      1234
      12345
      """
      for i in range(1, 6):
          for j in range(1, i + 1):
              print(j, end="")
          print()
output:     return ""