Added doBeforeSdk function

anko/library/static/commons/src/Helpers.kt

@@ -217,6 +217,14 @@ inline fun <T: Any> Fragment.configuration(
     else null
 }
 
+/**
+ * Execute [f] only if the current Android SDK version is [version] or older.
+ * Do nothing otherwise.
+ */
+inline fun doBeforeSdk(version: Int, f: () -> Unit) {
+    if (Build.VERSION.SDK_INT <= version) f()
+}
+
 /**
  * Execute [f] only if the current Android SDK version is [version] or newer.
  * Do nothing otherwise.
@@ -269,4 +277,4 @@ inline fun <T> attempt(f: () -> T): AttemptResult<T> {
         error = t
     }
     return AttemptResult(value, error)
-}
+}