Automattic / jetpack

			$taxonomy = $tax_query['taxonomy'];

			if ( ! isset( $args[ $taxonomy ] ) || ! is_array( $args[ $taxonomy ] ) ) {

				$args[ $taxonomy ] = array();

			}

			$args[ $taxonomy ] = array_merge( $args[ $taxonomy ], $tax_query['terms'] );

		}

		/* add terms by ID */

		foreach ( $input['terms_by_id'] as $taxonomy => $terms ) {

			// combine with any previous selections

			if ( ! isset( $tax_input[ $taxonomy ] ) || ! is_array( $tax_input[ $taxonomy ] ) ) {

				$tax_input[ $taxonomy ] = array();

			}

			$is_hierarchical = is_taxonomy_hierarchical( $taxonomy );