docs: def read_contents(self):
          '''Read all schemas in database'''
          cur = self.conn.cursor()
          cur.execute('''select nspname,
                                description
                          from pg_catalog.pg_namespace s
                          left join pg_catalog.pg_description d
                              on (d.objoid = s.oid)
                          where s.nspname not like 'pg\_%' and
                          s.nspname <> 'information_schema'
                          order by s.nspname''')
          schemas = cur.fetchall()
          cur.close()
          from pgdocgen.ddlobject.schema import Schema
          for (schema, comment) in [(x[0], x[1]) for x in schemas]:
              schema_obj = Schema(schema, comment, self.conn)
              self.contents.append(copy.deepcopy(schema_obj))
          self.conn.close()