This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.

raise 

        # Thread.raise

(from ruby core)
---
    thr.raise
    thr.raise(string)
    thr.raise(exception [, string [, array]])

---

Raises an exception from the given thread. The caller does not have to
be `thr`. See Kernel#raise for more information.

    Thread.abort_on_exception = true
    a = Thread.new { sleep(200) }
    a.raise("Gotcha")

This will produce:

    prog.rb:3: Gotcha (RuntimeError)
     from prog.rb:2:in `initialize'
     from prog.rb:2:in `new'
     from prog.rb:2

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