postgres query: not all arguments converted during string formatting
<p>Here is my code:</p>

<pre><code>conn = psycopg2.connect("dbname='test1' user='postgres' host='localhost' password='123'")
cur = conn.cursor()
query = "INSERT INTO product_info (product_name) VALUES (%s);"
data = ("ss")
cur.execute(query, data)

conn.commit()
</code></pre>

<p>I am not sure why i get the error:  not all arguments converted during string formatting, I can't figure out my syntax error</p>