here' simple function named greet_user(that prints greetinggreeter py def greet_user() """display simple greeting "" print("hello!" greet_user(this example shows the simplest structure of function the line at uses the keyword def to inform python that you're defining function this is the function definitionwhich tells python the name of the function andif applicablewhat kind of information the function needs to do its job the parentheses hold that information in this casethe name of the function is greet_user()and it needs no information to do its jobso its parentheses are empty (even sothe parentheses are required finallythe definition ends in colon any indented lines that follow def greet_user()make up the body of the function the text at is comment called docstringwhich describes what the function does docstrings are enclosed in triple quoteswhich python looks for when it generates documentation for the functions in your programs the line print("hello!"is the only line of actual code in the body of this functionso greet_user(has just one jobprint("hello!"when you want to use this functionyou call it function call tells python to execute the code in the function to call functionyou write the name of the functionfollowed by any necessary information in parenthesesas shown at because no information is needed herecalling our function is as simple as entering greet_user(as expectedit prints hello!hellopassing information to function modified slightlythe function greet_user(can not only tell the user hellobut also greet them by name for the function to do thisyou enter username in the parentheses of the function' definition at def greet_user(by adding username here you allow the function to accept any value of username you specify the function now expects you to provide value for username each time you call it when you call greet_user()you can pass it namesuch as 'jesse'inside the parenthesesdef greet_user(username)"""display simple greeting ""print("hellousername title("!"greet_user('jesse'