Creating an S3 Method (1)

By itself, the generic function doesn't do anything. For that, you need to create methods, which are just regular functions with two conditions:

The name of the method must be of the form generic.class.
The method signature - that is, the arguments that are passed in to the method - must contain the signature of the generic.

The syntax is:

generic.class <- function(some, arguments, ...) {
  # Do something
}

The generic get_n_elements() function has been defined in your workspace.

Type its name (without parentheses) to see how it works.
Write an S3 method to calculate the number of elements in a data.frame object.
- The name of the function should be the name of the generic, then a . then the name of the class of the input.
- The input arguments should be x and ....
- The body of the function should be a single line, returning the number of elements (rows times columns) in a data frame.
Call get_n_elements on the sleep dataset and assign the result to the variable n_elements_sleep.
Print n_elements_sleep to the console to see the result.