def _do_execute(self):
    '\n        Performs the actual execution.\n\n        :return: None if successful, otherwise error message\n        :rtype: str\n        '
    i = self.get('start')
    step = self.get('step')
    end = self.get('end')
    while (i <= end):
        self._output.append(i)
        i += step
    return None
Performs the actual execution.

:return: None if successful, otherwise error message
:rtype: str
def _do_execute(self):
    '\n        Performs the actual execution.\n\n        :return: None if successful, otherwise error message\n        :rtype: str\n        '
    i = self.get('start')
    step = self.get('step')
    end = self.get('end')
    while (i <= end):
        self._output.append(i)
        i += step
    return None