code: public static <A, B> B safeLookup(Map<A, B> map, A key) {
  
          if (map == null) {
              return null;
          }
          return map.get(key);
      }
docs: Helper method for looking up a value in a map which may be null.<p>
  
  @param <A> the key type
  @param <B> the value type
  @param map the map (which may be null)
  @param key the map key
  
  @return the value of the map at the given key, or null if the map is null