figure variables hold references to data objects figure assignment changes the reference print(( > and ( < )identifiers are used in programming languages as names in pythonidentifiers start with letter or an underscore ( )are case sensitiveand can be of any length remember that it is always good idea to use names that convey meaning so that your program code is easier to read and understand python variable is created when name is used for the first time on the left-hand side of an assignment statement assignment statements provide way to associate name with value the variable will hold reference to piece of data and not the data itself consider the following sessionthe_sum the_sum the_sum the_sum the_sum the_sum true the_sum true the assignment statement the_sum creates variable called the_sum and lets it hold the reference to the data object (see figure in generalthe right-hand side of the assignment statement is evaluated and reference to the resulting data object is "assignedto the name on the left-hand side at this point in our examplethe type of the variable is integer as that is the type of the data currently being referred to by "the_sum if the type of the data changes (see figure )as shown above with the boolean value trueso does the type of the variable (the_sum is now of the type booleanthe assignment statement changes the reference being held by the variable this is dynamic characteristic of python the same variable can refer to many different types of data introduction