A URL (Uniform Resource Locator) is an identifier used to locate resources on the web. A URL is composed of the following components: Scheme, Host Name (with optional Port Number), Path, (optional) Query String, (optional) Anchor. These components are arranged in the following format: Scheme://Hostname:Port/Path?QueryString#Anchor For example, in the URL "https://en.wikipedia.org:443/wiki/Kitten?printable=yes&download=no#External_links": "https" is the Scheme, "en.wikipedia.org" is the Hostname, 443 is the Port Number, "wiki/Kitten" is the Path, "printable=yes&download=no" is the Query String, and "External_links" is the Anchor. The Port Number is typically omitted when default port numbers are used by the hostname server (80 for http, 443 for https). When Path and Query String are empty, the '/' character before the Path becomes optional, e.g, as in the url: 'https://en.wikipedia.org'. Write a function url2hostname that takes in a URL and returns the hostname (without the port number). >> url2hostname('https://en.wikipedia.org:443/wiki/Kitten?printable=yes&download=no#External_links') ans = 'en.wikipedia.org' >> url2hostname('https://en.wikipedia.org/wiki/Kitten?printable=yes&download=no#External_links') ans = 'en.wikipedia.org' >> url2hostname('http://www.google.com') ans = 'www.google.com'