postgresql rookie needs help with system catalog

so far I have come up with the following query

  1 SELECT
  2        a.attname as "Column",
  3        pg_catalog.format_type(a.atttypid, a.atttypmod) as "Datatype"
  4    FROM
  5        pg_catalog.pg_attribute a
  6    WHERE
  7        a.attnum > 0
  8        AND NOT a.attisdropped
  9        AND a.attrelid = (
 10            SELECT c.oid
 11            FROM pg_catalog.pg_class c
 12                LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
 13            WHERE c.relname = 'laptop'
 14                AND pg_catalog.pg_table_is_visible(c.oid)
 15        );
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