<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get(self, aid):
 """ Get manga information by id. :param int aid: ID of the manga. :return: Dictionary or None (for not found) :rtype: Dictionary or None :raises: :class:`Pymoe.errors.ServerError` """

        r = requests.get(self.apiurl + "/manga/{}".format(aid), headers=self.header)

        if r.status_code != 200:
            if r.status_code == 404:
                return None
            else:
                raise ServerError

        return r.json()