@Override 
	public Enumeration<String> expertises()
	{
		return new Enumeration<String>()
		{
			final Iterator<Entry<String,Integer>> i=expertises.entrySet().iterator();
			@Override 
			public boolean hasMoreElements() 
			{ 
				return i.hasNext(); 
			}
			
			@Override 
			public String nextElement()
			{
				final Entry<String,Integer> s=i.next();
				if(s.getValue()==null)
					return s.getKey();
				return s.getKey()+s.getValue().toString();
			}
		};
	}