code: def _parse_positive_int_param(request, param_name):
    
    param = request.args.get(param_name)
    if not param:
      return None
    try:
      param = int(param)
      if param <= 0:
        raise ValueError()
      return param
    except ValueError:
      return -1
docs: Parses and asserts a positive (>0) integer query parameter.
  
    Args:
      request: The Werkzeug Request object
      param_name: Name of the parameter.
  
    Returns:
      Param, or None, or -1 if parameter is not a positive integer.