fix linting (#328)

integrations/pgvector/src/haystack_integrations/document_stores/pgvector/document_store.py

@@ -409,7 +409,7 @@ def _from_pg_to_haystack_documents(self, documents: List[Dict[str, Any]]) -> Lis
 
             # postgresql returns the embedding as a string
             # so we need to convert it to a list of floats
-            if "embedding" in document and document["embedding"]:
+            if document.get("embedding"):
                 haystack_dict["embedding"] = [float(el) for el in document["embedding"].strip("[]").split(",")]
 
             haystack_document = Document.from_dict(haystack_dict)