diff --git a/src/schema.ts b/src/schema.ts
index 28b39795..f96fd1de 100644
--- a/src/schema.ts
+++ b/src/schema.ts
@@ -14,13 +14,13 @@
  */
 import Ajv from 'ajv';
 import {JSONSchema7 as JSONSchema} from 'json-schema';
-import {filter} from 'lodash';
+import {chain} from 'lodash';
 import {Config, DEFAULT_CONFIG, Definition, SchemaGenerator} from 'ts-json-schema-generator';
 import {createFormatter} from 'ts-json-schema-generator/dist/factory/formatter';
 import {createParser} from 'ts-json-schema-generator/dist/factory/parser';
 import {createProgram} from 'ts-json-schema-generator/dist/factory/program';
 import {getTsconfigPath} from './common';
-import {definitionsOf, isLightweightClass} from './easy-ast/ast-util';
+import {definitionsOf} from './easy-ast/ast-util';
 import {lightweightProjectFromPath} from './easy-ast/easy-ast';
 import {isSchemaWithDefinitions} from './util/guards';
 import path from 'path';
@@ -113,7 +113,8 @@ export class Converter {
  * Get a list of validatable types from an API extractor file
  */
 export function getValidatableTypesInPath(path: string): string[] {
-  return filter(definitionsOf(lightweightProjectFromPath(path)), isLightweightClass)
-    .filter(type => type.comment?.tags?.find(it => it.name === 'validatable'))
-    .map(type => type.name);
+  return chain(definitionsOf(lightweightProjectFromPath(path)))
+    .filter(type => !!type.comment?.tags?.find(it => it.name === 'validatable'))
+    .map(type => type.name)
+    .value();
 }