In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Passage: Arthur Aloysius O'Leary was born on September 27, 1887, in Washington, D.C. His father was a worker on the Baltimore and Ohio Railroad. He was educated at Gonzaga College, and his parish was the adjacent St. Aloysius Church. He entered the Society of Jesus on August 14, 1903, and was sent to St. Andrew-on-Hudson in New York for his scholasticate. He then completed his studies at Woodstock College in Maryland, where he earned a Doctor of Philosophy. He went to Georgetown University in 1912, as a professor of philosophy, holding the position until 1916. At the same time, he was also spiritual director for the university. He was finally ordained a priest in 1919, becoming a member of the first class of priests ordained at Georgetown. He then returned to St. Andrew-on-Hudson, where he taught for several years.
Link Information: none Question: How many classes of priests have their been at Georgetown since O'Leary was ordained?
Answer: none