public static boolean unmap(String path, String httpMethod) {
        return getInstance().unmap(path, httpMethod);
    }
Unmaps a particular route from the collection of those that have been previously routed.
Search for previously established routes using the given path and HTTP method, unmaps any
matches that are found.

@param path          the route path
@param httpMethod    the http method
@return <tt>true</tt> if this is a matching route that has been previously routed
@throws IllegalArgumentException if <tt>path</tt> is null or blank or if <tt>httpMethod</tt> is null, blank,
or an invalid HTTP method
src/main/java/spark/Spark.java