code: def add_entry(self, entry):
          
          self.entry_keys.setdefault(entry, [])
          self.entries.append(entry)
          for dist in find_distributions(entry, True):
              self.add(dist, entry, False)
docs: Add a path item to ``.entries``, finding any distributions on it
  
          ``find_distributions(entry, True)`` is used to find distributions
          corresponding to the path entry, and they are added.  `entry` is
          always appended to ``.entries``, even if it is already present.
          (This is because ``sys.path`` can contain the same value more than
          once, and the ``.entries`` of the ``sys.path`` WorkingSet should always
          equal ``sys.path``.)