diff --git a/src/parser.jl b/src/parser.jl
index 182b861..9619315 100644
--- a/src/parser.jl
+++ b/src/parser.jl
@@ -214,7 +214,7 @@ end
 
 
 function parse_document_content(stream::EventStream)
-    if in(peek(stream.input), [DirectiveToken, DocumentStartToken, DocumentEndToken,StreamEndToken])
+    if peek(stream.input) isa Union{DirectiveToken, DocumentStartToken, DocumentEndToken,StreamEndToken}
         event = process_empty_scalar(stream, peek(stream.input).span.start_mark)
         stream.state = pop!(stream.states)
         event