code cleanup

Author: MaggieKimani1

src/Microsoft.OpenApi/Models/OpenApiDocument.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
@@ -464,14 +464,6 @@ internal T ResolveReferenceTo<T>(OpenApiReference reference) where T : class, IO
             }
         }
 
-        /// <summary>
-        /// Load the referenced <see cref="IOpenApiReferenceable"/> object from a <see cref="OpenApiReference"/> object
-        /// </summary>
-        public IOpenApiReferenceable ResolveReference(OpenApiReference reference)
-        {
-            return ResolveReference(reference, false);
-        }
-
         /// <summary>
         /// Takes in an OpenApi document instance and generates its hash value
         /// </summary>

src/Microsoft.OpenApi/Models/OpenApiParameter.cs

@@ -327,7 +327,7 @@ public void SerializeAsV2WithoutReference(IOpenApiWriter writer)
             }
             // In V2 parameter's type can't be a reference to a custom object schema or can't be of type object
             // So in that case map the type as string.
-            else if (Schema?.UnresolvedReference == true || "object".Equals(Schema?.Type.ToString(), StringComparison.OrdinalIgnoreCase))
+            else if (Schema?.UnresolvedReference == true || "object".Equals(Schema?.Type?.ToString(), StringComparison.OrdinalIgnoreCase))
             {
                 writer.WriteProperty(OpenApiConstants.Type, "string");
             }

src/Microsoft.OpenApi/Models/OpenApiRequestBody.cs

@@ -92,16 +92,6 @@ private void SerializeInternal(IOpenApiWriter writer, Action<IOpenApiWriter, IOp
             action(writer, target);
         }
 
-        /// <summary>
-        /// Returns an effective OpenApiRequestBody object based on the presence of a $ref
-        /// </summary>
-        /// <param name="doc">The host OpenApiDocument that contains the reference.</param>
-        /// <returns>OpenApiRequestBody</returns>
-        public OpenApiRequestBody GetEffective(OpenApiDocument doc)
-        {
-            return Reference != null ? doc.ResolveReferenceTo<OpenApiRequestBody>(Reference) : this;
-        }
-
         /// <summary>
         /// Serialize to OpenAPI V31 document without using reference.
         /// </summary>

src/Microsoft.OpenApi/Models/OpenApiSchema.cs

@@ -495,7 +495,7 @@ public void SerializeInternalWithoutReference(IOpenApiWriter writer, OpenApiSpec
             writer.WriteOptionalCollection(OpenApiConstants.Enum, Enum, (nodeWriter, s) => nodeWriter.WriteAny(new OpenApiAny(s)));
 
             // type
-            if (Type.GetType() == typeof(string))
+            if (Type?.GetType() == typeof(string))
             {
                 writer.WriteProperty(OpenApiConstants.Type, (string)Type);
             }