Normalized Func.as_sqlite() signature.

        template = template or self.extra.get('template', self.template)

        return template % self.extra, params

    def as_sqlite(self, *args, **kwargs):

        sql, params = self.as_sql(*args, **kwargs)

    def as_sqlite(self, compiler, connection):

        sql, params = self.as_sql(compiler, connection)

        try:

            if self.output_field.get_internal_type() == 'DecimalField':

                sql = 'CAST(%s AS NUMERIC)' % sql