Add nullability annotations to transformer classes.

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYDateTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 extern NSString * const BUYDateTransformerName; // = @"BUYDate";
 
@@ -32,5 +33,9 @@ extern NSString * const BUYDateTransformerName; // = @"BUYDate";
  * Transforms a date object into a string and back using the provided format string.
  */
 @interface BUYDateTransformer : NSValueTransformer
+
 + (instancetype)dateTransformerWithFormat:(NSString *)format;
+
 @end
+
+NS_ASSUME_NONNULL_END

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYDecimalNumberTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 extern NSString * const BUYDecimalNumberTransformerName; // = @"BUYDecimalNumber";
 
@@ -32,4 +33,7 @@ extern NSString * const BUYDecimalNumberTransformerName; // = @"BUYDecimalNumber
  * Transforms a decimal number object into a string and back.
  */
 @interface BUYDecimalNumberTransformer : NSValueTransformer
+
 @end
+
+NS_ASSUME_NONNULL_END

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYDeliveryRangeTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 extern NSString * const BUYShippingRateDateTransformerName; // = @"BUYShippingRateDate";
 extern NSString * const BUYShippingRateDateFormat; // = @"yyyy-MM-dd'T'HH:mm:ss.SSSZ";
@@ -32,3 +33,5 @@ extern NSString * const BUYShippingRateDateFormat; // = @"yyyy-MM-dd'T'HH:mm:ss.
 @interface BUYDeliveryRangeTransformer : NSValueTransformer
 
 @end
+
+NS_ASSUME_NONNULL_END

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYFlatCollectionTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 /**
  * Transforms an array of objects into a string with given separator.
@@ -44,3 +45,5 @@
 + (instancetype)setTransformerWithSeparator:(NSString *)separator;
 
 @end
+
+NS_ASSUME_NONNULL_END

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYIdentityTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 extern NSString * const BUYIdentityTransformerName; //  = @"BUYIdentity";
 
@@ -34,3 +35,5 @@ extern NSString * const BUYIdentityTransformerName; //  = @"BUYIdentity";
 @interface BUYIdentityTransformer : NSValueTransformer
 
 @end
+
+NS_ASSUME_NONNULL_END

Mobile Buy SDK/Mobile Buy SDK/Value Transformers/BUYURLTransformer.h

@@ -25,6 +25,7 @@
 //
 
 #import <Foundation/Foundation.h>
+NS_ASSUME_NONNULL_BEGIN
 
 extern NSString * const BUYURLTransformerName; // = @"BUYURL";
 
@@ -32,4 +33,7 @@ extern NSString * const BUYURLTransformerName; // = @"BUYURL";
  * Transforms a URL object into a string and back.
  */
 @interface BUYURLTransformer : NSValueTransformer
+
 @end
+
+NS_ASSUME_NONNULL_END