How can I find follow requested users with python-twitter

I am trying to follow some user in a list with python-twitter library. But I am taking "You've already requested to follow username" error for some users. That means I have sent a following request to that user so I cant do that again. So how can I control users, I sent following request. Or is there other way to control it.

for userID in UserIDs:
    api.CreateFriendship(userID)

EDIT: I am summerizing: You can follow some users when you want. But some ones don't let it. Firstly you must send friendship request, then he/she might accept it or not. What I want to learn is, how I can list requested users.

You have two options here:

• call GetFriends before the loop:

  users = [u.id for u in api.GetFriends()]
  for userID in UserIDs:
      if userID not in users:
          api.CreateFriendship(userID)
  

• use try/except:

  for userID in UserIDs:
      try:
          api.CreateFriendship(userID)
      except TwitterError:
          continue
  

Hope that helps.