computers and programs the is python prompt indicating that our genie (the python interpreteris waiting for us to give it command in programming languagesa complete command is called statement an interactive environment for interacting with an interpreter is called command shell or just shell for short here is sample interaction with python shellprint("helloworld!"helloworldprint( print(" =" here have tried out three examples using the python print statement the first statement asks python to display the literal phrase helloworldpython responds on the next line by printing the phrase the second print statement asks python to print the sum of and the third print combines these two ideas python prints the part in quotes followed by the result of adding which is this kind of shell interaction is great way to try out new things in python snippets of interactive sessions are sprinkled throughout this book when you see the python prompt in an examplethat should tip you off that an interactive session is being illustrated it' good idea to fire up your own python shell and try the examples usually we want to move beyond one-line snippets and execute an entire sequence of statements python lets us put sequence of statements together to create brand-new command or function here is an example of creating new function called hellodef hello()print("hello"print("computers are fun!"the first line tells python that we are defining new function and we are naming it hello the following lines are indented to show that they are part of the hello function (notesome shells will print ellipses ["at the beginning of the indented linesthe blank line at the end (obtained by hitting the key twicelets python know that the definition is finishedand the shell responds with another prompt notice that typing the definition did not cause python to print anything yet we have told python what should happen when the hello function is used as commandwe haven' actually asked python to perform it yet function is invoked (or calledby typing its name followed by parentheses here' what happens when we use our hello command