None can have a plural sense as in not any as well as a singular sense, not a single one. When followed by of, you need to assess the object of the preposition (the noun in the of phrase). If the object of the preposition is singular, then a singular verb is in order. If the object of the preposition is plural, one has some flexibility with verb choice. Mostly, but not always, you will use the plural verb.
None of the cake was eaten. (Cake is singular, so use a singular verb.)
None of the puppies were sleeping. (Puppies is plural, so use a plural verb. However, with English, that ever-fickle mistress, when none denotes not a single one, it is also correct to say, “None of the puppies was sleeping.”)
When writing your sentence, remember there is an implied noun that answers the question, “None of what?” Again, if that noun is singular, none requires a singular verb. If that noun is plural, it is up to you as the writer and the sense you are trying to convey in your sentence that determines whether or not none requires a singular verb or a plural verb.
None was eaten. (None of the cake was eaten.)
None were sleeping. (None of the puppies were sleeping. But you as the writer may prefer was as in, “Not a single one of the puppies was sleeping.”)
Somewhere along the way, the myth that none is solely singular appeared. Not only is this incorrect based on what I presented above, but it’s up to you, dear writer, to decide if your context is singular or plural. Now you have the information required to defend your choice.