minor refactor

src/commonMain/kotlin/com/infendro/cli/command/Execution.kt

@@ -28,11 +28,9 @@ class Execution(
         thisRef: Any?,
         property: KProperty<*>,
     ): T {
-        return parser.parse(
-            arguments
-                .find { it.name == name }!!
-                .value
-        )
+        return arguments
+            .single { it.name == name }
+            .let { parser.parse(it.value) }
     }
 
     operator fun <T> Argument.SingleOrElse<T>.getValue(
@@ -40,7 +38,7 @@ class Execution(
         property: KProperty<*>,
     ): T {
         return arguments
-            .find { it.name == name }
+            .singleOrNull { it.name == name }
             ?.let { parser.parse(it.value) }
             ?: other
     }
@@ -50,7 +48,7 @@ class Execution(
         property: KProperty<*>,
     ): T? {
         return arguments
-            .find { it.name == name }
+            .singleOrNull { it.name == name }
             ?.let { parser.parse(it.value) }
     }