function is code that performs some task and can be invoked by name the above code invokesor callsthe print(function with the text "helloworldas input the parentheses tell python to call the print(function they also enclose everything that gets sent to the function as input the quotation marks indicate that "helloworldreally is text and not something else note idle highlights parts of your code in different colors as you type to make it easier for you to identify the different parts by defaultfunctions are highlighted in purple and text is highlighted in green the interactive window executes single line of code at time this is useful for trying out small code examples and exploring the python languagebut it has major limitationyou have to enter your code one line at timealternativelyyou can save python code in text file and execute all of the code in the file to run an entire program the editor window you'll write your python files using idle' editor window you can open the editor window by selecting file new file from the menu at the top of the interactive window the interactive window stays open when you open the editor window it displays the output generated by code in the editor windowso you'll want to arrange the two windows so that you can see them both at the same time