code: public static function compose(callable $predicate, callable $function) : callable
      {
          return function ($element) use ($predicate, $function) {
              return Predicates::call($predicate, Functions::call($function, $element));
          };
      }
docs: Returns true for $x if $predicate($function($x)) is true.
  
  @param callable $predicate
  @param callable $function
  @return callable