diff --git a/index.d.ts b/index.d.ts
index 27b856b..0ab1b99 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,36 +1,42 @@
 import { JSONSchema4, JSONSchema6, JSONSchema7 } from 'json-schema';
 import { ErrorObject } from 'ajv';
 
-type Schema = JSONSchema4 | JSONSchema6 | JSONSchema7;
-type PostFormatter = (formattedError: string, error: ErrorObject) => string;
-
 declare namespace SchemaUtils {
+  type Schema = JSONSchema4 | JSONSchema6 | JSONSchema7;
+  type SchemaUtilErrorObject = ErrorObject & {
+    children?: SchemaUtilErrorObject[];
+  };
+  type PostFormatter = (
+    formattedError: string,
+    error: SchemaUtilErrorObject
+  ) => string;
+
+  interface ValidationErrorConfiguration {
+    name: string;
+    baseDataPath: string;
+    postFormatter: PostFormatter;
+  }
+
   class ValidationError extends Error {
     constructor(
-      errors: Array<ErrorObject>,
+      errors: Array<SchemaUtilErrorObject>,
       schema: Schema,
       configuration?: Partial<ValidationErrorConfiguration>
     );
 
     name: string;
-    errors: Array<ErrorObject>;
+    errors: Array<SchemaUtilErrorObject>;
     schema: Schema;
     headerName: string;
     baseDataPath: string;
     postFormatter: PostFormatter | null;
     message: string;
   }
-
-  interface ValidationErrorConfiguration {
-    name: string;
-    baseDataPath: string;
-    postFormatter: PostFormatter;
-  }
 }
 
-declare var validate: {
+declare const validate: {
   (
-    schema: Schema,
+    schema: SchemaUtils.Schema,
     options: Array<object> | object,
     configuration?: Partial<SchemaUtils.ValidationErrorConfiguration>
   ): void;