Accept [GRXWriter writerWithContainer:nil] for consistency with the rest
diff --git a/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m b/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
index 2050fa9..0387c99 100644
--- a/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
+++ b/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
@@ -59,7 +59,6 @@
// Designated initializer.
- (instancetype)initWithContainer:(id<NSFastEnumeration>)container {
- NSAssert(container, @"container can't be nil");
if ((self = [super init])) {
_container = container;
}