Answer: As a string, followed by the type.

In the new style of type hinting introduced in pandas API on Spark, Series names are specified directly within the return type annotation, using a concise format. For example, `-> pd.Series[str, int]` denotes a single Series with name 'str' and type int. This method enhances readability, type safety, and potential performance optimizations. It's a departure from traditional pandas type hinting where Series names were often specified within a dictionary. Note that this new style is experimental and may evolve in future releases.

Author: LeetQuiz Editorial Team