1 files changed, 1 insertions, 1 deletions
diff --git a/packages/assert/src/index.ts b/packages/assert/src/index.ts
index 938daab92..f3b3651d5 100644
--- a/packages/assert/src/index.ts
+++ b/packages/assert/src/index.ts
@@ -10,7 +10,7 @@ export const assert = {
         const isBigNumber = _.isObject(value) && (value as any).isBigNumber;
         this.assert(isBigNumber, this.typeAssertionMessage(variableName, 'BigNumber', value));
     },
-    isValidBaseUnitAmount(variableName: string, value: BigNumber) {
+    isValidBaseUnitAmount(variableName: string, value: BigNumber): void {
         assert.isBigNumber(variableName, value);
         const isNegative = value.lessThan(0);
         this.assert(!isNegative, `${variableName} cannot be a negative number, found value: ${value.toNumber()}`);