# File lib/fog/ibm/requests/compute/modify_key.rb, line 28
        def modify_key(key_name, params={})
          response = Excon::Response.new
          if key_exists? key_name
            if params['public_key']
              self.data[:keys][key_name]['keyMaterial'] = public_key
              self.data[:keys][key_name]['lastModifiedTime'] = Fog::IBM::Mock.launch_time
            end
            if params['default']
              self.data[:keys].values.each do |key|
                key['default'] = false
              end
              self.data[:keys][key_name]['default'] = true
            end
            response.status = 200
            response.body = {"success"=>true}
          else
            response.status = 404
          end
          response
        end