# File lib/error.rb, line 45
  def self.test extended_klass
    k = extended_klass
    CLASHING_INSTANCE_METHODS.each do |m|
      if k.method_defined?(m) or k.protected_method_defined?(m) or k.private_method_defined?(m)
        raise(
          self,
          "the class you are extending already defines instance method '#{m}'",
          caller
        )
      end
    end
    class_methods = k.methods + k.protected_methods + k.private_methods
    CLASHING_CLASS_METHODS.each do |name|
      if class_methods.include? name
        raise(
          self,
          "the class you are extending already defines class method #{name}",
          caller
        )
      end
    end
  end