Summary: The `block` paramenter is marked as nonnull, so we can't pass `nil` directly in. Reviewed By: dshahidehpour Differential Revision: D4929692 fbshipit-source-id: a35ef2940d6986f4ff55444d8a99ba17eb7c677e
Summary: The `block` paramenter is marked as nonnull, so we can't pass `nil` directly in. Reviewed By: dshahidehpour Differential Revision: D4929692 fbshipit-source-id: a35ef2940d6986f4ff55444d8a99ba17eb7c677e