Merge branch 'feature/optional_array' into 'develop'

optional array

See merge request BPHV_MIPS/mvm_core!9

MVMCore/MVMCore/Categories/Dictionary+MFConvenience.swift

@@ -52,6 +52,10 @@ public extension Dictionary {
         return array
     }
     
+    func optionalArrayForChainOfKeysOrIndexes(_ keysOrIndexes: [Any]) -> [Any]? {
+        return objectChainOfKeysOrIndexes(keysOrIndexes) as? [Any]
+    }
+    
     /// Returns a Dictionary after looking up the specified key. An empty dictionary is returned if a dictionary for the key does not exist
     func dictionaryForKey(_ key : String) -> [String : Any] {
         
@@ -76,6 +80,13 @@ public extension Dictionary {
         return arrayForChainOfKeysOrIndexes([key])
     }
     
+    func optionalArrayForKey(_ key : String) -> [Any]? {
+        guard let key = key as? Key else {
+            return nil
+        }
+        return self[key] as? [Any]
+    }
+    
     /// Return a Bool after looking up the specified key. This will return false if the key does not exist
     func boolForKey(_ key : String) -> Bool {