code: def validate(self):
          '''Validate all the entries in the environment cache.'''
  
          for env in list(self):
              if not env.exists:
                  self.remove(envf validate(self):
          '''Validate all the entries in the environment cache.'''
  
          for env in list(self):
              if not env.exists:
                  self.remove(env)
docs: Validate all the entries in the environment cache.