class_docstr: This class provides a set of methods to read, parse and answer
  questions about a single robots.txt file.
docstr: Sets the URL referring to a robots.txt file.
docstr_tok: ["Sets","the","URL","referring","to","a","robots.txt","file","."]
code: def set_url(self, url):
      """Sets the URL referring to a robots.txt file."""
      self.url = url
      self.host, self.path = urllib.parse.urlparse(url)[1:3]
  
imports: import collections
  import urllib.parse
  import urllib.request
label_desc: Use image node_id 4 for calling the RobotFileParser obj's underlying member method code with example usage: obj.set_url(url) without return types