This sparql query is incorrect....timeout when fetching from wikidata

[het-parekh]

SELECT ?label ?property ?thumbnail WHERE { ?entity rdfs:label ?label . ?entity wdt:""" + property_code[0] + """ ?property_id . ?property_id rdfs:label ?property . OPTIONAL { ?property_id wdt:P18 ?thumbnail .} FILTER (STR(?label) = '""" + named_entity[0] + """') . SERVICE wikibase:label { bd:serviceParam wikibase:language "en" . } }