Flow of Execution:
v The order in which statements are executed is called the flow of execution
v Execution always begins at the first statement of the program.
v Statements are executed one at a time, in order, from top to bottom.
v Function definitions do not alter the flow of execution of the program, but remember that statements inside the function are not executed until the function is called.
v Function calls are like a bypass in the flow of execution. Instead of going to the next statement, the flow jumps to the first line of the called function, executes all the statements there, and then comes back to pick up where it left off.
Note: When you read a program, don’t read from top to bottom. Instead, follow the flow of execution. This means that you will read the def statements as you are scanning from top to bottom, but you should skip the statements of the function definition until you reach a point where that function is called.