code: def get_if_set(self, addresses):
          
  
          with self._lock:
              results = []
              for add in addresses:
                  results.append(self._get_if_set(add))
              return results
docs: Returns the value set in this context, or None, for each address in
          addresses.
  
          Args:
              addresses (list of str): The addresses to return values for, if set
                  within this context.
  
          Returns:
              (list): bytes set at the address or None