Q$3.($a$)$ Write an implementation of the following function for computing an approximation to the derivative of a function. def diff$($f$,$ h$)$: $\text{'}\text{'}\text{'}$Return a function that approximates the derivative of the function $\text{'}$f$\text{'}($which is assumed to take one argument of type 'float' and returning a 'float'$)$ using the formula f$\text{'}($x$)$ ~ $($f$($x$+$h$)-$ f$($x$-$h$))/2$h where $\text{'}$h$\text{'}$ is a 'float'.$\text{'}\text{'}\text{'}$ # your code here $[5$ marks$]($b$)$ Explain what a decorator is in Python, and what the syntax for using a decorator is$.[5$ marks$]($c$)$ Give three examples of uses of decorators. $[3$ marks$]($d$)$ Write a logging decorator log such that after each call of a function to which the decorator is applied, the parameters and return value are printed as in the following example: def foo$($x$,$ y$)$: print$("$hello$!")$ return abs$($x$-$y$)$ After applying the decorator, when we call the function we would get: $>>>$ foo$(12,15)$ hello! foo$(12,15)=3$