It's still correct to this day. The article 'a/an' is often used when an uncountable noun is preceded by a qualifying adjective. 'I have an unparalleled admiration for Tolkien'.
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Lev Landaurain is an uncountable nounWhatever the dictionaries say, uncountable nouns can be used as countable nouns when the idea of "a certain kind of" is intended.