code: def Get(self, project_id):
      
      if project_id in self._emulators:
        return self._emulators[project_id]
  
      emulator = self.Create(project_id)
      self._emulators[project_id] = emulator
      return emulator
docs: Returns an existing emulator instance for the provided project_id.
  
      If an emulator instance doesn't yet exist, it creates one.
  
      Args:
        project_id: project ID
  
      Returns:
        a DatastoreEmulator