code: def validate(**vkargs):
      
      def decorator(func):
          def wrapper(**kargs):
              for key, value in six.iteritems(vkargs):
                  if key not in kargs:
                      abort(403, 'Missing parameter: %s' % key)
                  try:
                      kargs[key] = value(kargs[key])
                  except ValueError:
                      abort(403, 'Wrong parameter format for: %s' % key)
              return func(**kargs)
          return wrapper
      return decorator
docs: Validates and manipulates keyword arguments by user defined callables.
      Handles ValueError and missing arguments by raising HTTPError(403).