```ruby
module TokyoApi
  class Base < Vertebrae::Model
    def normalized_base_path
      "#{base_path}/"
    end

    def url_escape(string)
      CGI.escape(string)
    end

    def required_fields_param(required_fields)
      if required_fields.present?
        "required_fields=#{required_fields.collect{|v| url_escape(v.to_s)}.join(',')}"
      else
        ''
      end
    end
  end
end```

Make sure we only attempt to URL encode strings
user
```ruby
module TokyoApi
  class Base < Vertebrae::Model
    def normalized_base_path
      "#{base_path}/"
    end

    def url_escape(string)
      CGI.escape(string.to_s)
    end

    def required_fields_param(required_fields)
      if required_fields.present?
        "required_fields=#{required_fields.collect{|v| url_escape(v.to_s)}.join(',')}"
      else
        ''
      end
    end
  end
end```
assistant