As part of a data processing pipeline, complete the implementation of the make_pipeline method:

The method should accept a variable number of functions, and it should return a new function that accepts one parameter $arg.
The returned function should call the first function in the make_pipeline with the parameter $arg, and call the second function with the result of the first function.
The returned function should continue calling each function in the make_pipeline in order, following the same pattern, and return the value from the last function.

For example, make_pipeline(function($x) { return $x * 3; }, function($x) { return $x + 1; }, function($x) { return $x / 2; }) then calling the returned function with 3 should return 5.