class RSpec::Core::Configuration

def self.add_setting(name, opts={})
  raise "Use the instance add_setting method if you want to set a default" if opts.has_key?(:default)
  if opts[:alias]
    deprecate_alias_key
    define_aliases(opts[:alias], name)
  else
    attr_writer name
    define_reader name
    define_predicate_for name
  end
  [opts[:alias_with]].flatten.compact.each do |alias_name|
    define_aliases(name, alias_name)
  end
end