lback Callback executed to add payment requirements data.
	 * }
	 *
	 * @throws Exception On failure to register.
	 * @return boolean True on success.
	 */
	public function register_payment_requirements( $args ) {
		if ( ! is_callable( $args['data_callback'] ) ) {
			$this->throw_exception( '$data_callback must be a callable function.' );
		}

		$this->payment_requirements[] = $args['data_callback'];

		return true;
	}

	/**
	 * Returns the additional payment requirements.
	 *
	 * @param array $initial_requirements list of requirements that should be added to the collected requirements.
	 * @return array Returns a list of payment requirements.
	 * @throws Exception If a registered callback throws an error, or silently logs it.
	 */
	public function get_payment_requirements( array $initial_requirements = [ 'products' ] ) {
		$requirements = $initial_requirements;
		if ( empty( $this->payment_requirements ) ) {
			return $initial_requirements;
		}

		foreach ( $this->payment_requirements as $callback ) {
			$data = [];

			try {
				$data = $callback();

				if ( ! is_array( $data ) ) {
					throw new Exception( '$data_callback must return an array.' );
				}
			} catch ( Throwable $e ) {
				$this->throw_exception( $e );
				continue;
			}
			$requirements = array_merge( $requirements, $data );
		}

		return array_unique( $requirements );
	}

	/**
	 * Throws error and/or silently logs it.
	 *
	 * @param string|Throwable $exception_or_error Error message or Exception.
	 * @throws Exception An error to throw if we have debug enabled and user is admin.
	 */
	private function throw_exception( $exception_or_error ) {
		if ( is_string( $exception_or_error ) ) {
			$exception = new Exception( $exception_or_error );
		} else {
			$exception = $exception_or_error;
		}
		// Always log an error.
		wc_caught_exception( $exception );
		if ( defined( 'WP_DEBUG' ) && WP_DEBUG && current_user_can( 'manage_woocommerce' ) ) {
			throw $exception;
		}
	}

	/**
	 * Format schema for an extension.
	 *
	 * @param string $namespace Error message or Exception.
	 * @param array  $schema An error to throw if we have debug enabled and user is admin.
	 * @param string $data_type How should data be shaped.
	 *
	 * @return array Formatted schema.
	 */
	private function format_extensions_properties( $namespace, $schema, $data_type ) {
		if ( ARRAY_N === $data_type ) {
			return [
				/* translators: %s: extension namespace */
				'description' => sprintf( __( 'Extension data registered by %s', 'woocommerce' ), $namespace ),
				'type'        => [ 'array', 'null' ],
				'context'     => [ 'view', 'edit' ],
				'readonly'    => true,
				'items'       => $schema,
			];
		}
		return [
			/* translators: %s: extension namespace */
			'description' => sprintf( __( 'Extension data registered by %s', 'woocommerce' ), $namespace ),
			'type'        => [ 'object', 'null' ],
			'context'     => [ 'view', 'edit' ],
			'readonly'    => true,
			'properties'  => $schema,
		];
	}
}