A function definition introduces a new variable that refers to a function object. The return statement describes the value that will be produced as a result of the function when this function is done being executed.
A parameter is a variable that appears between the parentheses of a function header.
A local variable is a variable that is used in a function definition to store an intermediate result in order to make code easier to write and read.
A function call tells Python to execute a function.
An argument is an expression that appears between the parentheses of a function call. The value that is produced when Python evaluates the expression is assigned to the corresponding parameter.
If you made assumptions about the values of parameters or you know that your function won’t work with particular values, write a precondition to warn other programmers.