thesum sumrangelast step first in which we directly specify which argument is supposed to receive which value as we've seen earlierkeyword arguments can be used with the print(function to change the separation string that gets inserted when printing multiple arguments and to change the string printed at the end of the function call variable scope variables are classified by their scopewhich indicates where the variable was created and where it can be used python has four scope classifications the built-in scope includes the variables and literal values defined as part of the languagewhich can be used anywhere within program the global scope includes the variables created at the top level of source file or module (outside of all functions and classesunlike other languages in which global variable can be used anywhere within programeach module in python creates its own global scope the local scope includes the variables created within function or method and are local to the given subroutine function and method arguments are local variables and finallythe instance scope includes the variables defined as data attributes of class these will be discussed more in appendix variables only exist within the scope in which they were created the builtin and global scopes exist during the entire life of the program variables in the instance scope exist during the lifetime of the object for which they were defined local variablehoweveronly exists during the time in which the function is being executed each execution of function creates new local scopewhich is then destroyed when the function terminates main routine every program must have unique starting pointa first statement to be executed in pythonthe first statement to be executed is the first statement at file level (outside of all functions and class definitionsthe statements within function are not executed until the function is calledeven though the statements are interpreted and converted to byte code as they are read thusyou can refer to one function from within another before the former has been defined for exampleconsider the following code segmentdef run()value intinput("enter value"print"the double of your value is "doubleitvalue def doubleitnum )return num run(but this is not the case when calling function from statement at file level when python source file or module is loaded by the interpreterall statements at