rapid introduction to procedural programming piece # control flow statements |we mentioned earlier that each statement encountered in py file is executed in turnstarting with the first one and progressing line by line the flow of control can be diverted by function or method call or by control structuresuch as conditional branch or loop statement control is also diverted when an exception is raised in this subsection we will look at python' if statement and its while and for loopsdeferring consideration of functions to piece # and methods to we will also look at the very basics of exception-handlingwe cover the subject fully in but first we will clarify couple of items of terminology boolean expression is anything that can be evaluated to produce boolean value (true or falsein pythonsuch an expression evaluates to false if it is the predefined constant falsethe special object nonean empty sequence or collection ( an empty stringlistor tuple)or numeric data item of value anything else is considered to be true when we create our own custom data types ( in )we can decide for ourselves what they should return in boolean context in python-speak block of codethat isa sequence of one or more statementsis called suite because some of python' syntax requires that suite be presentpython provides the keyword pass which is statement that does nothing and that can be used where suite is required (or where we want to indicate that we have considered particular casebut where no processing is necessary the if statement the general syntax for python' if statement is thisif boolean_expression suite elif boolean_expression suite elif boolean_expressionnsuiten elseelse_suite in this bookellipses are used to indicate lines that are not shown