code: def get(self, external_site: str, external_id: int):
          
          r = requests.get(self.apiurl + "/mappings", params={"filter[externalSite]": external_site, "filter[externalId]": external_id}, headers=self.header)
  
          if r.status_code != 200:
            raise ServerError
  
          jsd = r.json()
  
          if len(jsd['data']) < 1:
            return None
  
          r = requests.get(jsd['data'][0]['relationships']['item']['links']['related'], headers=self.header)
  
          if r.status_code != 200:
              return jsd
          else:
              return r.json()
docs: Get a kitsu mapping by external site ID
  
          :param str external_site: string representing the external site
          :param int external_id: ID of the entry in the external site.
          :return: Dictionary or None (for not found)
          :rtype: Dictionary or None
          :raises: :class:`Pymoe.errors.ServerError`