# File lib/eventmachine.rb, line 1505
  def self.klass_from_handler(klass = Connection, handler = nil, *args)
    klass = if handler and handler.is_a?(Class)
      raise ArgumentError, "must provide module or subclass of #{klass.name}" unless klass >= handler
      handler
    elsif handler
      begin
        handler::EM_CONNECTION_CLASS
      rescue NameError
        handler::const_set(:EM_CONNECTION_CLASS, Class.new(klass) {include handler})
      end
    else
      klass
    end

    arity = klass.instance_method(:initialize).arity
    expected = arity >= 0 ? arity : -(arity + 1)
    if (arity >= 0 and args.size != expected) or (arity < 0 and args.size < expected)
      raise ArgumentError, "wrong number of arguments for #{klass}#initialize (#{args.size} for #{expected})"
    end

    klass
  end