def func(**kwargs)
 puts kwargs.class
 p kwargs
end

puts(:a => "alpha", :n => 1)
func(:a => "alpha", :n => 1)
puts(1 => "alpha")
puts(1 => 100)
# func(1 => "alpha") # wrong number of arguments (1 for 0) (ArgumentError)
# func(1 => 100) # wrong number of arguments (1 for 0) (ArgumentError)