public function maybe_filter_block( $content, $block ) {

		// Allow conditionally filtering the block based on external context.
		if ( ! $this->should_filter_block( $block ) ) {
			return $content;
		}

		// Set the `user_login` field block's visibility to its default 'logged_out' if not set.
		// The WordPress serializer `getCommentAttributes()` function removes the attribute before being
		// serialized into `post_content` if the attribute can have only one value and it's the default.
		if ( 'llms/form-field-user-login' === $block['blockName'] && empty( $block['attrs']['llms_visibility'] ) ) {
			$block['attrs']['llms_visibility'] = 'logged_out';
		}

		// No attributes or no llms visibility settings (visible to "all").
		if ( empty( $block['attrs'] ) || empty( $block['attrs']['llms_visibility'] ) ) {
			return $content;
		}

		$uid = get_current_user_id();

		// Show only to logged in users.
		if ( 'logged_in' === $block['attrs']['llms_visibility'] && ! $uid ) {

			$content = '';

			// Show only to logged out users.
		} elseif ( 'logged_out' === $block['attrs']['llms_visibility'] && $uid ) {
			$content = '';

			// Enrolled checks.
		} elseif ( 'enrolled' === $block['attrs']['llms_visibility'] && ! empty( $block['attrs']['llms_visibility_in'] ) ) {

			// Don't have to run any further checks if we don't have a user.
			if ( ! $uid ) {

				$content = '';

				// Checks for the "any" conditions.
			} elseif ( in_array( $block['attrs']['llms_visibility_in'], array( 'any', 'any_course', 'any_membership' ), true ) ) {

				$found = $this->get_enrollment_count_by_type( $uid, $block['attrs']['llms_visibility_in'] );
				if ( ! $found ) {
					$content = '';
				}

				// Checks for specifics.
			} elseif ( in_array( $block['attrs']['llms_visibility_in'], array( 'this', 'list_all', 'list_any' ), true ) ) {

				$relation = 'list_any' === $block['attrs']['llms_visibility_in'] ? 'any' : 'all'; // "this" becomes an "all" relationship
				if ( ! llms_is_user_enrolled( $uid, $this->get_post_ids_from_block_attributes( $block['attrs'] ), $relation ) ) {
					$content = '';
				}
			}

			// Not-Enrolled checks.
		} elseif ( 'not_enrolled' === $block['attrs']['llms_visibility'] && ! empty( $block['attrs']['llms_visibility_in'] ) ) {

			// Only need to check logged in users.
			if ( $uid ) {

				// Checks for the "any" conditions.
				if ( in_array( $block['attrs']['llms_visibility_in'], array( 'any', 'any_course', 'any_membership' ), true ) ) {

					$found = $this->get_enrollment_count_by_type( $uid, $block['attrs']['llms_visibility_in'] );
					if ( $found ) {
						$content = '';
					}

					// Checks for specifics.
				} elseif ( in_array( $block['attrs']['llms_visibility_in'], array( 'this', 'list_all', 'list_any' ), true ) ) {

					$relation = 'list_any' === $block['attrs']['llms_visibility_in'] ? 'any' : 'all'; // "this" becomes an "all" relationship
					if ( llms_is_user_enrolled( $uid, $this->get_post_ids_from_block_attributes( $block['attrs'] ), $relation ) ) {
						$content = '';
					}
				}
			}
		}

		/**
		 * Filters a blocks content after it has been run through visibility attribute filters
		 *
		 * @since 1.0.0
		 *
		 * @param string $content The HTML content for a block. May be an empty string if the block should be invisible to the current user.
		 * @param array  $block   Block data array.
		 */
		return apply_filters( 'llms_blocks_visibility_render_block', $content, $block );

	}