How to add custom headers to all apis in swagger doc

there is a way to add headers field in one api as document mentions, like below

class API::V1::Teachers < Grape::API
  resource :teachers do
    desc "get all teachers information" do
      headers XAuthToken: {
            description: 'Validates your identity',
            required: true
          },
          XOptionalHeader: {
            description: 'Not really needed',
            required: false
          }
    end
    success: API::V1::Entities::Teachers::Base
    get '' do
      teachers = Teacher.all

      present :teachers, teachers, with: API::V1::Entities::Teachers::Base
    end
  end
end

but is there a way to add same headers in all apis under certain resources or namespace?

Start with the Grape API example in the issue and trace how headers are represented in the generated Swagger documentation. Determine whether headers can be applied at a resource or namespace level; the issue is complete only when the supported behavior and its configuration are clearly established.