error: psycopg2.errors.UndefinedFunction: function similarity(text, text) does not exist

While tryig to create a similiarity search with postgres, bump into this error with this simple query

cur.execute("""

SELECT id, name, category, subcategory,

       (1 - (embedding <=> %s::vector)) AS semantic_score,

       similarity(name, CAST(%s AS text)) AS keyword_score,

       (0.7 * (1 - (embedding <=> %s::vector)) +

        0.3 * similarity(name, CAST(%s AS text))) AS final_score

FROM items

WHERE category = %s

ORDER BY final_score DESC

LIMIT 5;

""", (query_emb, query, query_emb, query, category))

To resolve this you need to activate pg_trgm extension. For some reason, I have to do it everytime and need to ensure that the extension is activated before my query can be successful.