class list2(list): # add a join method to lists
	def join(self, sep=' '): # default separator is a single space
		if not isinstance(sep,str): # the separator should be a string
			# a runtime error could be thrown here
			sep = str(sep) # for now, just convert s to a string
		output = '' # accumulate this as the output string
		inner = '' # for first time through the for loop
		for item in self: # iterate through the input
			output += inner + str(item) # convert item to string if not already
			inner = sep # use the separator string after the first time through
		return output # if input iterator is empty, returns the empty string