diff --git a/src/output/tptp.rs b/src/output/tptp.rs
index 7c4808f..7056ce0 100644
--- a/src/output/tptp.rs
+++ b/src/output/tptp.rs
@@ -271,7 +271,7 @@ where
 				write!(format, ")")?;
 			}
 
-			write!(format, ")")
+			Ok(())
 		};
 
 		match &self.formula