text: """Common indentation related utility implementations.
  
  Mainly following interfaces are defined:
  
  - make_spaces_for_html: Make spaces that multiplied 2 to
      specified indentation number.
  - append_spaces_to_expression: Append spaces to a expression string.
  """
  
  
  from typing import List
  
  
  def make_spaces_for_html(*, indent_num: int) -> str:
      """
      Make spaces that multiplied 2 to specified indentation number.
  
      Parameters
      ----------
      indent_num : int
          Indentation number.
  
      Returns
      -------
      spaces : str
          Result spaces string.
      """
      from apysc._validation import number_validation
      number_validation.validate_integer(integer=indent_num)
      number_validation.validate_num_is_gte_zero(num=indent_num)
      spaces: str = ' ' * (indent_num * 2)
      return spaces
  
  
  def append_spaces_to_expression(*, expression: str, indent_num: int) -> str:
      """
      Append spaces to a js expression string.
  
      Parameters
      ----------
      expression : str
          JavaScript expression string to add spaces to.
      indent_num : int
          Indentation number. If 1 is specified, then spaces will be 2.
  
      Returns
      -------
      expression : str
          Expression string after adding spaces.
      """
      if indent_num == 0:
          return expression
      lines: List[str] = expression.splitlines()
      spaces: str = make_spaces_for_html(indent_num=indent_num)
      for i, line in enumerate(lines):
          lines[i] = f'{spaces}{line}'
      expression = '\n'.join(lines)
      return expression
  