human
Complete this python program:
def adds_message_to_errors_dict(error_message):
assistant
#Here is the Python code you requested.

    """A decorator that asserts the the decorated validator adds a given
    error message to the `errors` dict.
    :param error_message: the error message that the validator is expected to
    add to the `errors` dict
    :type error_message: string
    Usage:
    @adds_message_to_errors_dict(\That login name is not available.\)
    def call_validator(*args, **kwargs):
    return validators.user_name_validator(*args, **kwargs)
    call_validator(key, data, errors)
    """
    def decorator(validator):
        def call_and_assert(key, data, errors, context):
            result = validator(key, data, errors, context)
            assert (errors[key] == [error_message]), 'Should    add    message    to    errors    dict:    {msg}'.format(msg=error_message)
            return result
        return call_and_assert
    return decorator