class Gem::OptionParser::Switch

def self.guess(arg)
  case arg
  when ""
    t = self
  when /\A=?\[/
    t = Switch::OptionalArgument
  when /\A\s+\[/
    t = Switch::PlacedArgument
  else
    t = Switch::RequiredArgument
  end
  self >= t or incompatible_argument_styles(arg, t)
  t
end