code: def to_str(instance, encoding='utf-8'):
      '''Convert an instance recursively to string.'''
      if isinstance(instance, str):
          return instance
      elif hasattr(instance, 'decode'):
          return instance.decode(encoding)
      elif isinstance(instance, list):
          return list([to_str(item, encoding) for item in instance])
      elif isinstance(instance, tuple):
          return tuple([to_str(item, encoding) for item in instance])
      elif isinstance(instance, dict):
          return dict(
              [(to_str(key, encoding), to_str(value, encoding))
                  for key, value in instance.items()])
      else:
          return instancf to_str(instance, encoding='utf-8'):
      '''Convert an instance recursively to string.'''
      if isinstance(instance, str):
          return instance
      elif hasattr(instance, 'decode'):
          return instance.decode(encoding)
      elif isinstance(instance, list):
          return list([to_str(item, encoding) for item in instance])
      elif isinstance(instance, tuple):
          return tuple([to_str(item, encoding) for item in instance])
      elif isinstance(instance, dict):
          return dict(
              [(to_str(key, encoding), to_str(value, encoding))
                  for key, value in instance.items()])
      else:
          return instance
docs: Convert an instance recursively to string.