# TIL in Clojure the complement function takes a predicate and
# returns a function that is like the original function but negates
# the results.
# E.g.
# def is_greater(a, b); a > b; end
# complement(:is_greater)[1, 2] # => true
def complement(method_name)
 lambda do |*args|
    !method(method_name).call(*args)
  end
end