old_contents: from django.core.cache import CacheKeyWarning, cache
  
  from health_check.backends import BaseHealthCheckBackend
  from health_check.exceptions import (
      ServiceReturnedUnexpectedResult, ServiceUnavailable
  )
  
  
  class CacheBackend(BaseHealthCheckBackend):
      def check_status(self):
          try:
              cache.set('djangohealtcheck_test', 'itworks', 1)
              if not cache.get("djangohealtcheck_test") == "itworks":
                  raise ServiceUnavailable("Cache key does not match")
          except CacheKeyWarning as e:
              self.add_error(ServiceReturnedUnexpectedResult("Cache key warning"), e)
          except ValueError as e:
              self.add_error(ServiceReturnedUnexpectedResult("ValueError"), e)
  
new_contents: from django.core.cache import CacheKeyWarning, cache
  
  from health_check.backends import BaseHealthCheckBackend
  from health_check.exceptions import (
      ServiceReturnedUnexpectedResult, ServiceUnavailable
  )
  
  
  class CacheBackend(BaseHealthCheckBackend):
      def check_status(self):
          try:
              cache.set('djangohealtcheck_test', 'itworks', 1)
              if not cache.get("djangohealtcheck_test") == "itworks":
                  raise ServiceUnavailable("Cache key does not match")
          except CacheKeyWarning as e:
              self.add_error(ServiceReturnedUnexpectedResult("Cache key warning"), e)
          except ValueError as e:
              self.add_error(ServiceReturnedUnexpectedResult("ValueError"), e)
          except ConnectionError as e:
              self.add_error(ServiceReturnedUnexpectedResult("Connection Error"), e)
  
subject: Add connection error exception for cache backend (#195)