code: def __addUser(self, new_user):
          
          self.__lockReadAddUser.acquire()
          if new_user not in self.__cityUsers and \
                  new_user not in self.__excludedUsers:
              self.__lockReadAddUser.release()
              self.__logger.debug("__addUser: Adding " + new_user)
              self.__cityUsers.add(new_user)
  
              myNewUser = GitHubUser(new_user)
              myNewUser.getData()
              myNewUser.getRealContributions()
  
              userLoc = myNewUser.location
              if not any(s in userLoc for s in self.__excludedLocations):
                  self.__processedUsers.append(myNewUser)
          else:
              self.__logger.debug("__addUser: Excluding " + new_user)
              self.__lockReadAddUser.release()
docs: Add new users to the list.
  
          :param new_user: name of a GitHub user to include in
              the ranking
          :type new_user: str.