code: def arg_as_array(self, arg, split_char="|"):
          
          valuesString = self.get_argument(arg, default=None)
          if valuesString:
              valuesArray = valuesString.split(split_char)
              return valuesArray
  
          return None
docs: Turns an argument into an array, split by the splitChar
  
          :param str arg: The name of the query param you want to turn into an array based on the value
          :param str split_char: The character the value should be split on.
          :returns: A list of values
          :rtype: list