Who needs static typing when we can roll our own?

uglifier.rb

# Starts on line 91 in uglifier-2.5.0
 
# Initialize new context for Uglifier with given options
#
# options - Hash of options to override Uglifier::DEFAULTS
def initialize(options = {})
  (options.keys - DEFAULTS.keys - [:comments, :squeeze, :copyright])[0..1].each do |missing|
  raise ArgumentError.new("Invalid option: #{missing}")
end