BP_Core_Nav::edit_nav( array $args = array(), string $slug = '', string $parent_slug = '' )

	public function edit_nav( $args = array(), $slug = '', $parent_slug = '' ) {
		if ( empty( $slug ) ) {
			return false;
		}

		// We're editing a parent!
		if ( empty( $parent_slug ) ) {
			$nav_items = $this->get_primary( array( 'slug' => $slug ), false );

			if ( ! $nav_items ) {
				return false;
			}

			$nav_item = reset( $nav_items );
			$this->nav[ $this->object_id ][ $slug ] = new BP_Core_Nav_Item( wp_parse_args( $args, (array) $nav_item ) );

			// Return the edited object.
			return $this->nav[ $this->object_id ][ $slug ];

		// We're editing a child.
		} else {
			$sub_items = $this->get_secondary( array( 'parent_slug' => $parent_slug, 'slug' => $slug ), false );

			if ( ! $sub_items ) {
				return false;
			}

			$sub_item = reset( $sub_items );

			$params = wp_parse_args( $args, (array) $sub_item );

			// When we have parents, it's for life, we can't change them!
			if ( empty( $params['parent_slug'] ) || $parent_slug !== $params['parent_slug'] ) {
				return false;
			}

			$this->nav[ $this->object_id ][ $parent_slug . '/' . $slug ] = new BP_Core_Nav_Item( $params );

			// Return the edited object.
			return $this->nav[ $this->object_id ][ $parent_slug . '/' . $slug ];
		}
	}