remove the step prefix to will be replaced by Given
        :param step: step text

def __remove_prefix(self, step):
        """
        remove the step prefix to will be replaced by Given
        :param step: step text
        """
        step_length = len(step)
        for k in KEYWORDS:
            step = step.lstrip(k)
            if len(step) < step_length:
                break
        return step