code: def rendered(self):
          
          expressions = {k: v for (k, v) in self.expressions.items() if v is not None}
          if self.refs.attr_names:
              expressions["ExpressionAttributeNames"] = self.refs.attr_names
          if self.refs.attr_values:
              expressions["ExpressionAttributeValues"] = self.refs.attr_values
          return expressions
docs: The rendered wire format for all conditions that have been rendered.  Rendered conditions are never
          cleared.  A new :class:`~bloop.conditions.ConditionRenderer` should be used for each operation.