diff --git a/benchmark/utils/DriverUtils.swift b/benchmark/utils/DriverUtils.swift
index f5b5398..74f59d6 100644
--- a/benchmark/utils/DriverUtils.swift
+++ b/benchmark/utils/DriverUtils.swift
@@ -208,14 +208,10 @@
     }
 
     if let x = benchArgs.optionalArgsMap["--sleep"] {
-      if x.isEmpty {
+      guard let v = Int(x) else {
         return .fail("--sleep requires a non-empty integer value")
       }
-      let v: Int? = Int(x)
-      if v == nil {
-        return .fail("--sleep requires a non-empty integer value")
-      }
-      afterRunSleep = v!
+      afterRunSleep = v
     }
 
     if let _ = benchArgs.optionalArgsMap["--list"] {