diff --git a/affinity.py b/affinity.py
index de7df91..46ed213 100644
--- a/affinity.py
+++ b/affinity.py
@@ -238,8 +238,8 @@ def to_parquet(self, path, engine="duckdb", **kwargs):
             kv_metadata = []
             for k, v in self.metadata.items():
                 if isinstance(v, str) and "'" in v:
-                    # must escape single quotes
-                    kv_metadata.append(f"{k}: '{v.replace("'", "''")}'")
+                    _v = {v.replace("'", "''")}  # must escape single quotes
+                    kv_metadata.append(f"{k}: '{_v}'")
                 else:
                     kv_metadata.append(f"{k}: '{v}'")
             self.sql(f"""