added flat bag

Author: OlgaPodo

graph/patterns/flat-bag.md

@@ -0,0 +1,33 @@
+# Flat Bag Pattern
+
+Microsoft Graph API Design Pattern
+
+### *A known pattern in Microsoft Graph is to model multiple variants of a common concept as a single entity type with all the potential properties plus an additional property to distinguish the variants.*
+
+
+## Problem
+
+API designer needs to model a small and limited number of variants of a common concept with a concise list of non-overlapping properties and consistent behavior across variant. The designer also wants to simplify query construction.
+
+## Solution
+
+The API designer creates one entity type with all the potential properties plus an additional property to distinguish the variants, often called `variantType`.
+
+## Issues and Considerations
+
+????
+
+
+## When to Use this Pattern
+
+The flat-bag pattern is useful when there is a small number of variants 
+
+????
+
+There are related patterns to consider such as
+[Type Hierarchy](https://github.com/microsoft/api-guidelines/tree/graph/graph) and [Flat
+bag of
+properties](https://github.com/microsoft/api-guidelines/tree/graph/graph).
+
+## Example
+?????

graph/patterns/subtypes.md

@@ -106,7 +106,7 @@ Response payload shortened for readability:
     ]
 }
 ```
-API request for a subtype specific property requires type casting to the subtype, i.e. to retrieve jobTitle property, enabled for the user type, you need to cast from the directoryObject collection items to the microsoft.graph.group derived type.
+API request for a subtype specific property requires type casting to the subtype, i.e. to retrieve jobTitle property, enabled for the user type, you need to cast from the directoryObject collection items to the microsoft.graph.user derived type.
 
 ```
 GET https://graph.microsoft.com/v1.0/groups/a94a666e-0367-412e-b96e-54d28b73b2db/members/microsoft.graph.user?$select=displayName,jobTitle