code: public Auth retrieve(String nsid) {
      	Auth auth =  this.auths.get(nsid);
      	if(auth != null)
      		return auth;
      	else
      		return this.authsByUser.get(nsid);
      }
docs: /*
  (non-Javadoc)
  Retrieve via flickr user id or username.
  
  @see com.flickr4java.flickr.util.AuthStore#retrieve(java.lang.String)