You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: request_permission.rb
    path of file: ./repos/forest-rails/app/services/forest_liana/ability/permission
    
    the code of the file until where you have to start completion: require 'jwt'

module ForestLiana
  module Ability
    module Permission
      class RequestPermission
        def self.d
    
        def self.decodeSignedApprovalRequest(params)
          if (params[:data][:attributes][:signed_approval_request])
            decode_parameters = JWT.decode(params[:data][:attributes][:signed_approval_request], ForestLiana.env_secret, true, { algorithm: 'HS256' }).try(:first)

            ActionController::Parameters.new(decode_parameters)
          else
            params
          end