# File lib/fog/aws/models/iam/policies.rb, line 26
        def get(identity)
          requires_one :username, :group_name

          response = if self.username
                       service.get_user_policy(identity, self.username)
                     else self.group_name
                       service.get_group_policy(identity, self.group_name)
                     end

          new(response.body['Policy'])
        rescue Fog::AWS::IAM::NotFound
          nil
        end