code: private Optional<ResolvedType> find(Map<Node, ResolvedType> map, LambdaExpr lambdaExpr) {
          for (Node key : map.keySet()) {
              if (key instanceof LambdaExpr) {
                  LambdaExpr keyLambdaExpr = (LambdaExpr) key;
                  if (keyLambdaExpr.toString().equals(lambdaExpr.toString()) && getParentNode(keyLambdaExpr) == getParentNode(lambdaExpr)) {
                      return Optional.of(map.get(keyLambdaExpr));
                  }
              }
          }
          return Optional.empty();
      }
docs: For some reasons LambdaExprs are duplicate and the equals method is not implemented correctly.
  
  @param map
  @return