type calls to linked-in functionsexercise java classes under jythonand more partly because of its interactive naturepython supports an experimental and exploratory programming style you'll find convenient when getting started although python programmers also test with in-file code (and we'll learn ways to make this simple later in the book)for manythe interactive prompt is still their first line of testing defense usage notesthe interactive prompt although the interactive prompt is simple to usethere are few tips that beginners should keep in mind ' including lists of common mistakes like the following in this for referencebut they might also spare you from few headaches if you read them up fronttype python commands only first of allremember that you can only type python code at python' promptnot system commands there are ways to run system commands from within python code ( with os system)but they are not as direct as simply typing the commands themselves print statements are required only in files because the interactive interpreter automatically prints the results of expressionsyou do not need to type complete print statements interactively this is nice featurebut it tends to confuse users when they move on to writing code in fileswithin code fileyou must use print statements to see your output because expression results are not automatically echoed rememberyou must say print in filesbut it' optional interactively don' indent at the interactive prompt (yetwhen typing python programseither interactively or into text filebe sure to start all your unnested statements in column (that isall the way to the leftif you don'tpython may print "syntaxerrormessagebecause blank space to the left of your code is taken to be indentation that groups nested statements until all statements you write will be unnestedso this includes everything for now remembera leading space generates an error messageso don' start with space or tab at the interactive prompt unless it' nested code watch out for prompt changes for compound statements we won' meet compound (multilinestatements until and not in earnest until but as previewyou should know that when typing lines and beyond of compound statement interactivelythe prompt may change in the simple shell window interfacethe interactive prompt changes to instead of for lines and beyondin the idle gui interfacelines after the first are instead automatically indented you'll see why this matters in for nowif you happen to come across prompt or blank line when entering your codeit probably means that you've somehow confused interactive python into thinking you're typing multiline how you run programs