def get( key:, allow_throw: false )
      key = normalise_key( key, 'get' )

      begin
        @storage_engine_instance.get( key: key )
      rescue
        raise if allow_throw
      end
    end
def get( key:, allow_throw: false )
      key = normalise_key( key, 'get' )

      begin
        @storage_engine_instance.get( key: key )
      rescue
        raise if allow_throw
      end
    end
Retrieve data previously stored with #set.

 _Named_ parameters are:

 +key+::         Key previously given to #set.

 +allow_throw+:: If +true+, exceptions raised by the underlying storage
                 engine are thrown, else ignored and +nil+ is returned.
                 Optional; default is +false+.

 Returns +nil+ if the item is not found - either the key is wrong, the
 stored data has expired or the stored data has been evicted early from
 the storage engine's pool.

 Only non-empty String or Symbol keys are permitted, else an exception
 will be raised.