code: def start_import(self, version_id=None):
          
          if not version_id:
              version_id = self.version.id
  
          target_url = self._client.get_url('VERSION', 'POST', 'import', {'layer_id': self.id, 'version_id': version_id})
          r = self._client.request('POST', target_url, json={})
          return self._deserialize(r.json(), self._manager)
docs: Starts importing this draft layerversion (cancelling any running import), even
          if the data object hasn’t changed from the previous version.
  
          :raises Conflict: if this version is already published.