docs: def _to_boolean(string):
      """
      Transforms a string into a boolean value.
  
      If a value which is not 'Y' or 'N' is received, a ParseException is thrown.
  
      :param: string: the string to transform
      :return: True if the string is 'Y', False if it is 'N'
      """
  
      if string == 'Y':
          result = True
      elif string == 'N':
          result = False
      else:
          raise pp.ParseException(string, msg='Is not a valid boolean value')
  
      return result