Map<@NonNls String, MLFeatureValue> calculateFeatures(@NotNull LookupElement element,
                                                        @NotNull CompletionLocation location,
                                                        @NotNull ContextFeatures contextFeatures);
Map<@NonNls String, MLFeatureValue> calculateFeatures(@NotNull LookupElement element,
                                                        @NotNull CompletionLocation location,
                                                        @NotNull ContextFeatures contextFeatures)