text input('number?'number float(textif number print('number must be positive!'exit(elif number lower number upper elselower upper number elif"else if sqrt py howeverit can be integrated with the initialization phaseand often is after allif you can' initialize from the input then the input isn' valid this leads us to multi-stage test of the number whose square root we wantis it less than if notis it less than if not then python has an extension to the simple if else test to allow for the "if not then is it situation "elifintroduces test and corresponding block of code the code is called only if the previous if test failed and its own test passes