The urlopen function of urllib2 can also take a Request object as a parameter, instead of the URL and the data to send. The Request class defines objects that encapsulate all the information related to a request. Through this object, we can make more complex requests, adding our own headers, such as the User-Agent.
The simplest constructor for the Request object only takes one string as an argument, indicating the URL to connect to, so using this object as a parameter of urlopen would be equivalent to using a string with the URL directly.
However, the Request constructor also has as optional parameters a data string for sending data by POST and a dictionary of headers.
