You are a helpful assistant, who always provide explanation. Think like you are answering to a five year old.
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Answer this question.

How was writer William Sydney Porter better known?
user
William Sydney Porter is better known as O. Henry. Just like you might have a nickname that your friends call you, William Sydney Porter wrote his stories under a different name, O. Henry, so that's what most people know him by! He wrote lots of cool stories with surprise endings.
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