text: Most or a value that represents the results of the computation. Functions defined within class statements
  The fact that functions are ordinary, known as formal parameters or just parameters, that get bound to the values supplied as arguments when the function is called. In the simplest case, a function doesn't have any formal parameters, which means the function doesn't take any arguments when it is called. In this case, the function definition has empty parentheses after function-name.
  When a function does take arguments, parameters contains one or more identifiers, separated by commas (,). In this case, each call to the function supplies values, known as arguments, corresponding to the parameters listed in the function definition. The parameters are local variables of the function (as we'll discuss later in this section), and each call to the function binds these local variables to the corresponding values that the caller supplies as arguments.
  The nonempty twice the value passed to it each time it's called:
  def double(x):
  return x*2
  Formal.
  A's.
  ith.