function createSortedIndex(retHighest) {
	      return function(array, value, iteratee, thisArg) {
	        var callback = getCallback(iteratee);
	        return (iteratee == null && callback === baseCallback)
	          ? binaryIndex(array, value, retHighest)
	          : binaryIndexBy(array, value, callback(iteratee, thisArg, 1), retHighest);
	      };
	    }
Creates a `_.sortedIndex` or `_.sortedLastIndex` function.

@private
@param {boolean} [retHighest] Specify returning the highest qualified index.
@returns {Function} Returns the new index function.