code: def authorization_code(self, request, data, client):
          
          grant = self.get_authorization_code_grant(request, request.POST,
                  client)
          if constants.SINGLE_ACCESS_TOKEN:
              at = self.get_access_token(request, grant.user, grant.scope, client)
          else:
              at = self.create_access_token(request, grant.user, grant.scope, client)
              rt = self.create_refresh_token(request, grant.user, grant.scope, at,
                      client)
  
          self.invalidate_grant(grant)
  
          return self.access_token_response(at)
docs: Handle ``grant_type=authorization_code`` requests as defined in
          :rfc:`4.1.3`.