1 files changed, 0 insertions, 13 deletions
diff --git a/Firestore/third_party/Immutable/FSTArraySortedDictionary.m b/Firestore/third_party/Immutable/FSTArraySortedDictionary.m
index ad1d68a..e9325a7 100644
--- a/Firestore/third_party/Immutable/FSTArraySortedDictionary.m
+++ b/Firestore/third_party/Immutable/FSTArraySortedDictionary.m
@@ -142,19 +142,6 @@ NS_ASSUME_NONNULL_BEGIN
   }
 }
 
-- (nullable id)predecessorKey:(id)key {
-  NSInteger pos = [self findKey:key];
-  if (pos == NSNotFound) {
-    [NSException raise:NSInternalInconsistencyException
-                format:@"Can't get predecessor key for non-existent key"];
-    return nil;
-  } else if (pos == 0) {
-    return nil;
-  } else {
-    return self.keys[pos - 1];
-  }
-}
-
 - (NSUInteger)indexOfKey:(id)key {
   return [self findKey:key];
 }